Okay so I got this system a few years ago from CyberPower and feel like it's time for an upgrade. I play mainly RTS and Assassins Creed/Mass Effect - what's the first thing I should upgrade for most bang for my buck? Price range is about $3-400 for upgrades. Thanks!
CU-202-201 INTEL i7-860 2.80GHZ 8M LGA 1156 RETA
HD-403-108 1TB SATA II 3.0 GB 7200RPM HD
64 GB SSD (boot disk) HD
RM-317-108 2 GB DDR3 PC3 PC1333
MB-351-101 ASUS P7P55D LE P55 CROSSFIRE DDR3 LGA
MISC ONBOARD 7.1 SOUND 1 0.00 0.00
VC-189-101 EVGA NVIDIA GEFORCE GTX 275 896MB P 1 166.00 166.00
Go with 8 gb of ram; it's only $40 where I live. Year end sales are on in the usa; newegg has a new ad out today: http://promotions.newegg.com/NEemail/dec-0-2011/AfterCh....
Everything else looks good. You won't get that much performance adding a second video card. You should also list your power supply specs. Always.
I would highly suggest 2x 4GBs for a Windows 7 system. www.crucial.com can help you locate one guaranteed to work with the board.
I am a bit antsy about the Kingwin 700w PSU. They aren't well known as far as I can tell, but at least some of them are made by Super Flower which is a new brand but was iirc the first brand to bring platinum grade PSUs to the market.
I am going to shy away from saying to change out the PSU, but I will say that I prefer brands that are more well known when I am thinking about what to trust my parts to and I suggest that for others too.
You might want to consider going with a new video card with some of the budget. The GTX 275 is starting to show its age now, but it should still do pretty well most of the time.
For about $140 a HD 6850 should be able to get about 50% more FPS.
Also, I don't know what your case is, but I will assume it is generic since you didn't mention it.
A good case can go a long way towards making your parts work better and last longer. You could consider getting a case with some of the budget. Antec 300 Illusion is highly recommended, so is the HAF series from Cooler Master, and Lian Li is another great brand as well.
Lian Li is a premium brand, but often you can find their cases on sale for a reasonable price. I got mine for $60 shipped and I feel like I ripped Newegg off. I don't think $60 shipped should be able to buy this much case.
Anyway, that is another option for a way to spend a portion of the budget to take things to the next level.
You can probably get a good set of 2x 4GB, a 6850, and a pretty good case all together under $300.