Do you run oom when using essentially all the consumables you can? If no, go pure +healing. If yes, get some spirit or mp5 in whatever ways you can get more mana while sacrificing as little +healing as possible. Making +healing socket bonuses be using purified shadowsong amethysts is a good one. Swapping to the vastly better if mana is an issue insightful earthstorm is also a good one. Becoming an alchemist and using the amazing redeemer's alchemist stone is another.

There's something I think worth noting when looking at the amount of regen you get from the Bangle of Endless Blessings. It has a kind of internal synergy between its proc and on use effects; that is, I've noticed a huge upgrade in mana gained if I wait until I have the Meditation buff up before clicking the trinket. Raid buffed (without spirit) tonight I was getting just over 300 mp5, and when I had Meditation and the extra 130 spirit, I was at like 430 mp5. Now, that's only going to last for 15 seconds (and will probably only affect 5 of the 6 ticks), but that's a significant increase in regen at the cost of waiting for the trinket to proc. (The only part where the math gets futzy is when you consider that sometimes you'll go a full minute or more without getting a proc.) Couple this with using the Darkmoon: Blue Dragon card's proc and you get even more regen. My druid's build is built around spirit regen--unbuffed he's at 537 sprit, 481 intellect, 604 mp5 / 219 mp5 in and out of the fsr. That's an awful lot for my progression level, but that's just my playstyle. My point, though, is that if you combine the Bangle's on use effect with its own procs and the Darkmoon card procs, you might see even more mana regen than the numbers tell you you'll get.

I have no idea how to interpret this into mathy numbers, so I'm just gonna wing this part and throw a little bit of caution to the wind. Feel more than free to correct my numbers, assumptions, and calculations, as I'm pretty new to theorycrafting.

The numbers I've come up with for my toon are:
676 Spi
603 Int
92 mp5;
which should net me
866 mp5 outside of the fsr, and 324 mp5 inside it.

(774 of the regen is the Int/Sprit, 92 comes from mp5 on gear and from Wisdom.)

I should say at this point that I usually sit around 300 mp5 raid buffed (we usually don't have Divine Spirit), and this number is always more than enough of a base for me to work from in raids. If I'm in the tank group (most of the time), I can get enough regen over a ten-minute fight between my Bangle and my Innervate to survive. I don't have to pot much. So why do I want more regen? Because I like big numbers.

So let's say that I'm using the Bangle and the Blue Dragon card (which I will be testing this week). Every minute I'll get an extra 15% regen for 15 seconds, every two minutes I'll get an extra 100% for 15 seconds, and every two minutes I'll get an extra +130 spirit. First I'll calculate these values separately, then I'll attempt to mush them together like an abomination.

Bangle Proc: +15% is an extra (774*0.15) = 116 mp5 for 15 seconds, or 348 mana per proc. (348 mana / 60 seconds)
Darkmoon: +100% is an extra (774*1) = 774 mp5 for 15 seconds, or 2322 mana per proc. (1161 mana / 60 seconds)
Bangle Use: +130 spirit makes the Int/Spi 914 mp5, which means 274 mp5 in the fsr (Intensity), for 20 seconds; with Mp5 gear/buffs, this is 366 mp5, or 42 additional mana per 5 (over 324, above), totaling 630 mana. (315 mana / 60 seconds) (Phew, there's probably an error there. Please feel free to correct me.)

So now I'll do calculations combining Procs with the Bangle Use:

Bangle Proc + Use: +15% is an extra (914*0.15) = 137 mp5 for 15 seconds, or 411 mana. (+63 mana from Use.)
Darkmoon Proc + Use: +100% is an extra (914*1) = 914 mp5 for 15 seconds, or 2742 mana. (+420 mana from Use.)
**Also note that both situations above would also gain the 630 mana from the Bangle's Use alone.**

And just for fun:
Bangle Proc + Darkmoon Proc + Bangle Use:
366 (Int/Spi/Mp5) + 914 (Darkmoon) + 137 (Bangle) = 1417 mp5 for 15 seconds, 4251 mana.
It's like a mini Innervate. Speaking of...
366 + 914 + 137 + 3656 (914*4*1, right?) = 5073 mp5 for the stacked Innervate. Big numbers, squee!

See, that last number being so big tells me I'm doing something wrong here. Am I? Or is Spirit-based regen with the right itemization just really freaking good?

This post is more or less a way for me to get started theorycrafting my Druid. Please, please correct me anywhere you see a mistake so I can figure out where my character has room to spare for improvements. I know that in terms of raid viability the situations I'm describing aren't all that pragmatic. However, with a guild that's just progressing into MH and BT, I feel like being able to survive a little longer might come in handy. I'm just exploring the best way to do that.

P.S., is the +130 spirit gained from the Bangle affected by Living Spirit? (Freakin' monkey wrench into my math there if it does.)

Next I wanna get some input on if having 676 spirit and the Raven Goddess Idol is worth it as opposed to, say, 600 spirit and the Idol. (I think 213 extra healing is cool. Big numbers.)

It is affected by the Living Spirit talent, but all your mathematics seem quite awkvard to me.
Are really considering wearing both of these trinkets at the same time, gimping your healing into oblivion?
And on another note: I can't even think of a fight where this level of regen is viable or needed.
Between your own innervate, an occasional pot (which are just fabulous if you have the alchemy trinket), gemming some items with Purified Shadowsong Amethysts (like t6 shoulders, rage/t6 bracers, life step belt, etc) you should already have a suffiecient manapool for anything this game throws at you, even without grouping with a shadowpriest

(my experience is currently up to brut in SP)

Although I've wanted it for some time, I just got the Bangle the other day and used it in a quick VR/Sol run last night. I was skeptical about its usefulness (I have the LCPB and Martyr) but wanted to see how it would perform. I found the proc rate to be satisfactory but streaky, leaving me with less mana at some points than the tried-and-true LCPB. I tend to chain-cast (can't seem to run out of mana unless I try and we've been short of healers lately) and was actually finding myself running low on mana because the Bangle didn't proc. From a mana regen perspective the Bangle was unimpressive, particularly with the large amount of spirit I already have. I think I'll try one more time, activating the on-use effect when I think I can stop chain-casting for a while or simply use it when the trinket itself procs.

I don't think anyone would say the LCPB can be passed up because of the large healing. It's particularly good for a druid because of how rapid we can cast spells during its duration. Because the mana-regen on it is an on-use, I can front-load my mana regen so to speak instead of the Bangle which, because you have to wait for it to proc, is back-loaded.

Personally, I do innervate myself but even without the Bangle or any special procs I can't help but have full mana and more to spare at the end of the innervate, even chain-casting for the duration. The new spirit-based regen is incredible and makes the Bangle overkill. I tend to stack spirit as a secondary stat (gem with Purified Shadow Pearls). If anything the +spirit bonus on the Bangle could be seen as a on-click +healing bonus due to ToL aura and IDS.

K, well, as you realize you didn't include spirit in your calc. But in addition to that:
The Darkmoon card is not +100%. It's +70%, you already have 30% of your mana regen from Intensity. So 774x0.7=542mp5 for for 15 seconds or 1626 mana per proc.
You've calculated it at a bonus 42mp5 while the bangle's Use effect is active. It lasts for 20 seconds. 42mp5x4=210 mana. Where did your 630 mana come from? 210 every 2 minutes is 8.75mp5.
You're Bangle Proc + Use effect seems right. An additional 63 mana every 2 minutes works out to 2.6mp5.
Darkmoon Proc + Use: Again, you should be using +70%, not 100%, so 914*0.7 = 640mp5 for 15 seconds or 1920 mana. This is a gain of 294mana (also note 420*0.7=294), once every 2 minutes, or 12.25mp5.

Your Bangle Proc + Darkmoon + Proc + Bangle Use calc is not at all relevant. If Darkmoon Procs you are already at 100% mana return. The bangle proc does nothing to add to this. Likewise, innervating will completely negate the procs from either trinket, since with innervate you are no longer affected by the fsr. So in fact, while using the bangle in conjunction with innervates (overkill) and blue dragon procs will increase your mana return, you actually lose some of the proc effects from the bangle due to overlap.

As an aside, you commented that you don't have to pot that often. If you don't have to pot, but are using two mana regen trinkets, then you are hurting your healing because you're cheap. Pony up the dough for pots and sacrifice some of your personal regen. It will make you a better healer.

Edit: Just to elaborate on the 'overkill' bit when you use the bangle with an innervate - yes, it would provide huge returns (as noted in the above post), but nearly any PvE druid will have a full mana bar after 20s of innervate even without the bangle use, so this theoretical mana gain can never actually be obtained. Also, you can basically bump all my numbers that include the bangle Use effect up by 15% to include living spirit.

First of all thanks for pointing out the 70% thing. I did most of this in 2 separate sessions, probably why there's a weird error here and there. I figured that there was no way you could get above 100% regen, but I hadn't ever seen it said, so that helps too.

In regards to your aside: I don't use two mana regen trinkets. I usually keep one equipped if I'm without a shadowpriest, and I've tweaked my regen enough to the point where potting is something I only have to do if I'm spamming regrowth or something. My +healing is 1740, it's not what you'd call weak. But there are some fights where I'm asked to use my innervate on a holy priest, in which case I'm on my own for regen, which is why I wanna know what I'm looking at as far as numbers from these two trinkets (separate and together). I don't ever have as much +healing as anyone else in the raid, but I'm the one with the best longevity and I can push myself harder in the big raid damage fights, so usually I end up topping the healing meters, especially in the progression fights (which are all that really matter to my guild).

The tip about Innervate overriding the procs is handy.

To Arkoth: I'm in T4/SSC/TK loot. My guild is starting Hyjal today. I'm trying to get my regen hammered down so I can start to stack healing.

Best I can figure, raid buffed the Card is worth 22.5 mp5 to me, assuming the 70% and one proc every two minutes. That's the number I was really looking for. This tells me switching to the card is really worth it now, as I've got a good Innervate staff for when I need the extra spirit.

To Daedalix: You use Essence and a Prayerbook? You could probably do with just using the Prayerbook and the Bangle.

What's your hangup with using potions? Then you could start to stack +healing right now.

Not using mana potions and optimizing your gear around using them is a simple statement that doing more healing is not worth a couple gold to you. While that may be a fairly common idea throughout the wow community, its not here.

Some people play for the team, some people play for themselves.

Why? And lose 84 healing? Perhaps I wasn't clear enough in my post... I can't pour mana out fast enough and I barely have to chug pots now and again. Mana regen isn't an issue for anything we're working on right now (Hyjal and Vashj) I was considering the Bangle as a possible replacement for the LCPB in mana-intensive situations but I just don't see it being viable or worth the tradeoff. The strength of the new spirit regen makes this argument hardly worth the time for anyone nominally geared. The LCPB scales much better with haste gear and I'll prolly use it till we down Illidan.

Stacking +healing as the primary stat is the current paradigm.

Please show us a WWS of that fight. Chain casting regrowth still means a 1350 per mp5 output, 1208 with the idol. Even with mana tide, a spriest and chain potting plus alchemist trinket and the darkmoon card blue you will have a hard time to keep that up for 6 minutes.

Did you downrank or do you mean casting when needed with chain casting?