EDIT: This is now continued here:
http://forums.elitistjerks.com/viewtopic.php?id=6825

As I've commented before, we Mages don't have it as interesting as Rogues or even Hunters as far as fun DPS optimization, but I figured I'd crunch the basic numbers to help give some insight as to stat allocation.

I'll just use my own stats for this (gear/talents in profile). I have a slightly more mana-friendly set (heavy NW) that I built up as well, but I've been using it less often since I got more MP/5 on my main gear, so I'm working stuff out for this set. Assuming basic raid buffs (Int, Spi, Mark, BoW, BoK) and no consumables:
370 Int (7002 mana)
224 Spi (281 with "Evocation Gear")
61.6 MP/5
+7% Hit
11.22% Crit chance (kind of low at the moment)
+648 Frost damage
+554 Arcane

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First, assume I use Missiles on Clearcasts, and Frostbolt at all other times. Some things to remember:
--We'll assume no casting lag for now, since it's an enormous pain.
--Doing this, it's still impossible to perfectly chaincast a Missiles after a Frostbolt, because you don't see the Clearcast pop up until about halfway through the next Frostbolt. I'll assume you waste about 1s cancelling it and starting the Missiles. You sometimes also need this time to get into Missiles range.
--A double Clearcast lets you spend an unusual amount of time out of the 5SR.
--I generally give the slightest pause between finishing the Missiles and going back to the Frostbolt (say about half a second). It helps ensure a second full mana tick during the Frostbolt cast, and I'm sometimes also backing up to max range (depending on the fight).

In an average "block" of casting, then, I cast 9 Frostbolts and 1 Missiles in 29 seconds.

Damage done:
9*(535+648*.814)*1.19*(.83+.07+.112) + (230*5+554)*1.13*(.83+.07+.112/2) = 12,492

Mana used (gross):
9*246 = 2214

Mana regained:
Spirit:
(224/4+12.5)*0.3*29/2 = 298.0
MP5:
61.6*29/5 = 357.3
JoW. What the hell is proc rate of JoW (bolded to catch attention of someone who might know)? I have no idea. 50% seems reasonable. Each cycle has 14 chances to proc:
14*59*.5 = 413
Residual mana regen due to Clearcast-related 5SR abuse:
I find that, on average, a Clearcast on a Frostbolt is good for just under 2 full ticks of mana between clicking the Missiles and completing the next Frostbolt. A Clearcast on a Missiles is good for 2.5 ticks. I'll use 2 as an average value.
(224/4+12.5)*0.7*2 = 95.9

Total returns: 1164.2

Net usage: 1049.8

DPS: 430.8
MPS: -36.2

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For reference, without switching to Missiles:
A 2.5s Frostbolt does (535+648*.814)*1.09*(.83+.07+.112) = 1278
Mana cost = 246*.9 = 221.4
Mana return = (224/4+12.5)*0.3*2.5/2 + 61.6*2.5/5 + 59*.5 = 86.0

DPS: 511.2
MPS: -54.2

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With Missles, but using R4 Frostbolt (2.1s cast, for a 25.4s "block"):

Damage:
9*(78+648*(2.6/3.5*.95))*1.19*(.83+.07+.112) + (230*5+554)*1.13*(.83+.07+.112/2) = 6,777

Mana usage: 9 * 56 = 504

Mana returns:
Spirit: (224/4+12.5)*0.3*25.4/2 = 261.0
MP5: 61.6*25.4/5 = 312.9
The other two terms are the same.
Total: 1082.8

DPS: 266.8
MPS: +22.8

Note: I've actually been using R5 for this, but given what people said on the Combat Mechanics thread about level 20 spells, I'm going to switch to R4.

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Wanding (Touch of Chaos):
DPS: 82.0
MPS: (224/4+12.5)/2 + 61.6/5 + 59*.5/1.5 = +66.2

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Total Mana Resources
Starting Mana: 7002
3 Gems: 2550 (Any fight lasts long enough to use 3 Gems).
Evocation: (281/4 + 12.5)*16*4.9 = 6487 (4.9 ticks of Evoc, assuming you successfully "prime" the first three to 1.3x magnitude).

Total: 16039

Time to empty using CC'ed Missiles: 443 seconds (190,849 damage dealt)
Time to empty using Frostbolts only: 296 seconds (151,387 damage dealt)

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Sustainable DPS (no net mana consumption)

Even starting from 0, we don't DPS at constant mana--we regen up until we're at the point where shifting back to a full-DPS cycle will leave us empty again exactly as the fight ends. The average works out the same way, however.

1) Regen by Wanding
You must spend 36.2/(36.2 + 66.2) = 35.4% of your time wanding
DPS: .354*82 + .646*430.8 = 307.3

2) Regen by R4 Frostbolt
You must spend 36.2/(36.2 + 22.8) = 61.4% of your time casting R4
DPS: .614*266.8 + .386*430.8 = 330.1

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So, at first glance, in the 147 seconds left after I burn all my mana chaincasting Frostbolt, I can do 48,525 more damage, seemingly beating the person who tried to use Missiles. This warrants futher exploration--is Missiles ever worth using at all?

More importantly--with the basic framework laid down, we can look at the marginal benefits of different stats in verious length fights. At this point, however, I'm probably going to take this into spreadsheet form. Stay tuned.

50% from http://thottbot.com/?sp=20355

Oh, forgot to check there. Well good, I don't have to change anything.

Hmm, seemed higher, like around 60% to me. I'll look around and see if I can get a second opinion. If not, I'll turn on Recap and do the testing myself.

Pretty minor difference:
I was under the impression that caster mechanics are a little different in regards to resist/crit because a caster "crit" can be rolled as resisted (more evident as fire, since you see partial crits, but parsing enough frost bears this out as well I think). Rather than adding them up shouldn't the bolded portions be:

[(0.83+0.07)*(1+0.1122)] and [(0.83+0.07)*(1+0.1122/2)]

Note that I haven't worked "resists" (nonzero target resist stats) into this at all yet. As fas as I know, "white resists" work just like melee misses--they don't affect crit chance, but stat-based resists work in the way you described.

It's much, much better than spellhit. Assuming the change in wording makes it work like Shadow Focus, it can reduce the chance to resist to zero, and will reduce yellow resists in addition to level-based resists.

Yes. You want at least one point in it. Most builds will probably bump it up to three, but if you have a decent amount of +spell hit (and especially if you have 5/5 Enigma) then you can probably get away with just one.

re the OP: This is a completely unscientific observation, but I've found that at least as far as sustained damage goes it's just better to chaincast Frostbolt in most situations. If I attempt to use the clearcast to squeeze in Missiles, it causes me to lose DPS versus other classes.