Well, I heavily redid my UI over the weekend. Had a few days off of raiding, and figured it would be nice with ICC progression coming up. I've iterated on it a few times now in AV and other places, looking forward to seeing how it feels in a raid. Feedback would be great, I want to tweak it to a final state over the next week before hardmodes.
Basic layout is similar to the previous one (here:
http://elitistjerks.com/attachments/...309_201137.jpg ), but a lot of space is saved, a lot of things are made more effective, and it's much more polished aesthetically. First, a basic look in AV:

I'll note straightaway the duplicative cooldown info (the SexyCooldown bar, and the action buttons right above my player frame). Haven't yet decided which I like better--more on that later.
A main goal was to keep a large area immediately around my character clear. The raid frames don't come as close to my left side and the casting info to my feet as before. The unit frames are further down--I've found that they're not important enough, especially while healing, to need to be right in my face. Any important info concerning my HP and buffs is in the raid frames anyway. Other things I don't need to look at every second are even further down--Auracle pane showing what raid buffs I have, RaidCooldowns, miscellaneous buffs that I never really need to check in combat, and minimap, and chat frame.
The raid frames are the major part of what I changed. I made them in RDX, which, if you don't know what it is, I wouldn't plan on using (but if you want to put in a lot of time learning to use an extremely complex mod, is amazing). I basically said to myself, what the things, in order of priority, I want to know about raid members? It went:
1) Is their HP full, not full, low, or dead? (95% of the time, all I really need to know is which of those 4 categories they're in)
1a) Are they a Spirit of Redemption? (rare fifth category, but important for Rebirth reasons)
2) Are they in range?
3) If low, are they Swiftmendable?
4) Are they being targeted?
5) Do they have any cleansable debuffs or important boss debuffs?
6) Do they have my Rejuvenation on them?
7) Do they have my other HoT's, and what durations?
8) What's their exact HP level?
9) What class are they?
10) What's their name?
11) Do they have someone else's Rejuvenation, PWS, or incoming heals on them? (just to see what other healers are doing)
12) Is their mana low?
13) Do they have Gift of the Wild?
I decided my Grid setup wasn't accomplishing these things well. It overemphasized 8, 9, and 10, generally made it hard to make anything besides HP really prominent (unless you made the CenterIcon so big that it obscured other things), and gave me no way of doing 3. I set out to make some frames from scratch that focused their most eye-catching properties on things at the top of the list. Here's another shot:
Important properties:
--The total area of each frame is smaller than my Grid boxes (18x128 vs. 45x55).
--HP bars are only half the width of the frame, so some things can be shown without covering it. By they're still longer than the Grid boxes, so I still have better resolution on the HP.
--HP text only shows thousands (and no meaningless "k" after each one). White when full, pink when not full.
--HP bars are black. Color is only for things that need to get my attention. Missing HP and border is green (default), blue (low), or red (aggro).
--If HP is low, and the target is Swiftmendable, and Swiftmend is off cooldown, a large Swiftmend icon appears over part of the HP bar (see first shot).
--Background on either side of the bar is black (default, same idea as with HP), green/purple (curse/poison), blue (important boss debuff), yellow (SoR), or red (dead).
--Debuff icon is to the left (anything that used to be in Grid CenterIcon, basically). It obscures half the player's name (which is unimportant), instead of HP.
--Rejuv and Lifebloom get their own space on the side of the bar so I instantly see their coverage looking down the raid. Rejuv also highlights the frame border green.
--All other indicators are tiny--still easily to check, but never grab attention.
Enough about the frames. Here's the overall layout with everything in config mode (remember that makes things look more cluttered):

I'm not sure the SexyCooldown bar is necessary--might be redundant with the actionbar cooldowns and the buff/debuff in the middle right.
In contrast, here's how it looks clean:

And then of course, I picked a consistent font and bar texture for every mod, an uniform background color (gray, slightly transparent), centered things to pixel, etc. etc. All in all I'm happy, but I wound up spending quite a lot of time on it, and some fresh eyes would be nice.