Great I would probably switch for this ASRock Z68 Extreme3 Gen3 LGA 1155 Intel Z68 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard for $123 after MIR including shipping.
Switch to either this RAIDMAX SMILODON Extreme Black ATX-612WEB 1.0mm SECC Steel ATX Mid Tower Foldout MB Computer Case for $65 after MIR including shipping OR this COOLER MASTER Storm Scout SGC-2000-KKN1-GP Black Steel / Plastic ATX Mid Tower Computer Case for $70, (my preference). - Have we hit EXTREME YET Darn I guess not You got $12 left.
Save it for an aftermarket cooler. In a couple of months or so you might want to start giving the 2500K a nice overclock and could probably use something like this COOLER MASTER Hyper 212 EVO RR-212E-20PK-R1 Continuous Direct Contact 120mm Sleeve CPU Cooler Compatible with latest Intel 1366/1155 for only $35. But If it were me I would save a little more and get this CORSAIR H100 (CWCH100) Extreme Performance Liquid CPU Cooler for currently $109. But I'm a watercooling man who started out on these types of self contained all in one units so I can't help it.
I plan to make myself a playable gaming PC for the maximum budget of $750.
Here's what I currently think of putting in there:
ASUS P8Z68-V PRO
Corsair Vengeance 4 GB
Intel Core i3-2100
Sapphire Radeon HD 6790
Cooler Master Elite 310 ATX
Asus 24x DVD RW Drive
Western Digital 250 GB
I think it should work, but if you spot any flaws or have better ideas then please tell.
Your build is good considering your resolution. If you can manage Radeon HD 6850, it will be excellent & use a cooler master/antec/FSP/corsair PSU.
I have played CRYSIS DirectX10 64-bit on a Pentium dual-core E5300 @ 2.6GHz & Radeon HD 5670 1GB GDDR5 on HIGH settings with 2xAA at avg. 24 FPS @ 1360x768. Gameplay was surprisingly smooth
But which build would be better when considering I might want to upgrade in the future for better parts?
I might rather go with suteck's idea, actually. And I can increase my budget to buy a decent cooler, too.
If you go with my idea and the second list of parts when your budget went up a little you can do some more upgrading in the future as you suggested. 2 extra slots for memory so you can double that to 16 gigs for only about $50. And you'll also be able to add a second video card down the road - might need a higher wattage psu since the single card's peak is 364Watts. I would plan on a second card doubling that even though that's not what really happens. But I wouldn't want to be at or too close to my psu's max output. It tends to put too much strain on one so it won't last as long. You could probably go for a minimum of this Antec EarthWatts Series EA-750 Green 750W ATX12V v2.3 SLI Certified CrossFire Certified 80 PLUS BRONZE Certified Active PFC Continuous Power Supply. And it's only $55 right now after MIR, which is cheaper than the first one I suggested. Then you would be ready for the upgrade.
And HEY, That is a decent cooler lol. The trick is to put higher cfm fans on it - that's right fanS! It will do a lot better then. Unless you're talking about THIS H-100, it would be great for cooling when you start doing big overclocks. But first I would update/grade the monitor/tv to something that can take advantage of that/those video cards. When your talking about the sound card. You can do that if you're planning on hooking you machine to a surround sound system. Otherwise you would probably be wasting your money, However, down the road if you are able to hook one up you can always get an audio card then. But the asrock mobo already has an s/pdif optical out so I would try that first and see if it does what you want.