Thanks for the information. I have Win 7 64-bit and planning to install it soon.
PSU is the Thermaltake W0106RU 700W 80+ certified. Hopefully the PSU will last me up until the next Elder Scroll game.
Planning to upgrade the Mobo and CPU in 6 months or so.
So would you say something like (order of upgrade): GPU -> Mobo & CPU & RAM -> HDD?
Would you recommend a 2GB GPU like Radeon 7850 ... or would a 1GB GPU (like the Radeon 6850) be enough? I'm looking for something that will last me until the next ES (or 3-5 years). Play mainly heavily modded RPGs and Action RPGs, visuals are important, but not essential.
If you're for sure going to upgrade the CPU+MOBO+RAM around the 6 month time frame, then the Radeon 7850 2GB is a decent choice. That VRAM is going to help if you use a whole lot of texture mods. And do make that switch to Win 7 to make full use of your 4GB of RAM. In the meantime, try to overclock that E6750 a bit more if possible to relieve some of the bottlenecks you may see.
The PSU is average at best, but it will hold you over. The Radeon 7850 is rather friendly on the power consumption.
If you don't need a new HDD now, then that can wait. The Thailand flood impact on prices are starting to subside a bit. Hopefully, we'll see $50-$75 1TB drives again soon. An SSD is still a bit of a luxury but they too are dropping in prices and give a nice performance boost in your daily PC use and load times.
So basically, the gameplan you laid out is pretty much what I would have in mind

Looking for input on this rig
edit: link not working, 1 min.
Spoiler http://www.newegg.com/Product/Product.aspx?Item=N82E16813138341
http://www.newegg.com/Product/Product.aspx?Item=N82E16819106009
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231455
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150540
http://www.newegg.com/Product/Product.aspx?Item=N82E16817148046
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136950
http://www.newegg.com/Product/Product.aspx?Item=N82E16827106333
http://www.newegg.com/Product/Product.aspx?Item=N82E16811154109
Intending to get 2 of the 6770's. a Link to the "Wish List" wasnt working

Good idea, bad idea? The case is just a place-holder.
I've never crossfired, or had dual GPUs before. Currently running a single 6870, would the two 6770's be an improvement?
I couldnt find a AMD motherboard with PCI-E 3.0

so the 7xxx series seem kind of meaningless to get right now. Or am I wrong?
Get this CPU+MOBO Combo:
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.876433
That PSU is trash. Apevia has never made an even average PSU. 700W on that is a joke. And that extra speed on the RAM isn't going to warrant you much. Here's a couple combos for a decent PSU and cheaper RAM:
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.904258
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.904267
Rosewill has done well with the Hive series. Yes, Rosewill has history of mix-bag PSUs, but these are pretty good and the cheapest decent quality modular PSUs on the market:
http://www.hardwaresecrets.com/article/Rosewill-HIVE-650-W-Power-Supply-Review/1460/1
I'd vouch much more for a Caviar Black Drive (performance) than a Caviar Green (more for storage):
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136795
Try to get a Radeon 7770 or better the 6850 if possible. I'm not a fan of Crossfire or SLI for that matter. Performance gains is dependent on the game support and drivers and it can vary from no gain to 90%. I'd rather stick with a single powerful card and avoid the driver/game hassles, the heat, the extra power consumption, and the feeling of not getting my moneys worth when I don't see double performance. As a former SLI user, I've found it to be a bad idea since ditching that setup.
PCI-E 3.0 is going to be backwards and forwards compatible with all iterations of PCI-E x16, so it's alright to consider a 7-series card for a PCI-E 2.x supported board...there aren't really any cards that are close to saturating that bandwidth...most certainly not a Radeon 77xx or 78xx card.
The case, well...that's your choice. Cheapest cases I've worked with that I considered decent are the NZXT Source 210 and the NZXT Gamma. $40, free ship at Amazon.