All of which adds up to about $1150 before taxes and shipping.
So, as for my remaining questions:
I'm completely lost when it comes to PSUs, and so went by some of the tools and guides I found on here. Is the one I have picked out sufficient for my needs and for some light OC'ing? I assume it wouldn't be sufficient if somewhere down the line I wanted to add another graphics card; what about (see below) unlocking the 6950, how would that change my power reqs?
How about the case - it's not overkill, is it? I thought about the Antec 300 as well.
Once I have the thing constructed, does anyone have any comments on how difficult it would be to OC the 2500k just a little bit? It's something I want to do if it's easy and possible, but I want to make sure I know what I'm doing. Along those same lines, is a separate cooler necessary if I'm not going far above baseline?
Similarly to the OC'ing issue, how about unlocking the 6950 to a 6970 - comments or thoughts on doing that?
This is my first effort, so don't be too harsh! Thanks!
So it looks like you have the main setup pretty good but i fine tuned it a little. All the prices are from newegg, but check with microcenter before you buy. When i built my computer newegg had the i7-860 for $300 but i got it at microcenter for $200.
Case - yours is fine, the antec 300 or haf 922 are also good cases - $70-100
harddrive - spinpoint f3 500 tb - faster $50 (or get 1tb model for $55 on newegg for limited time with the code they have)
GPU - 6950 is a good choice, i included 2 in your build, but you can drop one if you want and add it later - $490
PSU - corsair 750tx - $110 - better for if you decide to crossfire the 6950's in the future (or now) 650 is pushing it a bit
RAM - g.skill 4gb kit - $50-55 - 8gb is overkill for gaming, 4gb is perfect
cpu cooler - hyper 212+ - $35 - for overclocking
CPU+MOBO combo - i5-2500k + GA-P67A-UD4-B3 - $395
total : $1225 after shipping - $75 MIR's = 1150
Add $100 if you need windows 7
SSD is optional, but for a pc mainly for gaming, it shouldnt be your top priority. It wont effect gaming much, but you get nice boot times. I'd get a 60-90gb OCZ vertex 2, agility 2...intel x25m...basically any ssd with the latest ssd driver or intel.
To answer some of your other question:
Overclocking the i5 is very easy and you will find plenty of guides to help you on the internet. I believe many i5's have been able to around 4ghz on the stock cooler. If you wish to proceed further safely, an aftermarket cooler is recommend to keep temperatures within a safe range.
As for flashing the 6950 bios to 6970. Just remember that your 6950 will have the same chip that was rejected from being a 6970 card. This doesnt mean that its a bad chip, but that it wasnt as "perfect" as the others put in the 6970. So if you do flash it, dont count on it working, it might be unstable, or it might run perfectly and still have some room to oc.