Ok forgot to put something useful in my last post sorry lol here it is:
Seagate's 7200.11's had a firmware issue a few months ago (recently), and their higher capacity drive models are extremely unreliable (like your 1tb drive, horrible reviews, keeps dieing after 3 months), but they do perform much better than the WD Caviar Blue series (the value brand from WD), so I'd suggest you get a nice reliable Caviar Black, which is much better than your Seagate, and is much more reliable, and has lower seek times. When I said 7200.11 had better performance, I meant raw data input/output, so that doesn't necessarily mean that copying small files ie. burst read/write will be good on it. That's where lower seek times help, so levels load faster in games.
Google short stroking, basically means that you keep all your applications and programs etc on the outside of your platters, and your data inside, for better performance.
If you're keeping that mobo, I'd suggest you get some cheap HD4770's, specifically 2 of them, exact same model. Put them in Crossfire. And there's no such thing as a VX650 lol. There's a VX550, and a TX650. No VX650, sorry
. The VX series won't feed two 4770's but they will feed your gtx260 no problem. For Crossfiring two 4770's, you'll need something from the TX series. I'd recommend the TX750, since it is the most reliable and respected of the 3 in the TX series. I haven't really heard of anyone using the VX series, and you should use Crossfire to get the most out of your mobo, so a TX750 and two HD4770's, should cost you approximately the same price if you're buying them on sale. TX750's go on sale more often than VX's, anyways. If you need CUDA, stick with the GTX260. Then again, you're using an AMD cpu, and ATI is the same company as AMD, so there's a nice match