my experience...
you should buy a seperate PSU that doesnt come with the case...
I got 2 cases that came with PSU's, and i had to replace them both.
- The 350watt psu was 11.7v on the +12v rail... thats low but not super low.. and it actually worked with a 2.8celeronD.. Problem was that occationaly it would not turn on, or not turn off lol.
- The 450watt psu didnt work at all... so i opend it up and took it apart... and looked at the bottom circuit board, and it appears that it was either built or rebuilt by a 10yr old indian sweatshop worker or someone that shouldnt have been weilding a Soldering iron, because they were probably a hazard to themself and otheres lol. Id post a pic if i had one at the moment.
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the xp3000, 1gb ram, 6600gt.. that i tested... ran HL2 and Doom3 at Medium to High settings. anything bellow a 6600gt and you would proably be running (Low to Medium) settings at best.
The best bang for your buck card now though is the (6800 128mb 256bit) card for 160 to 180.
Its out of stock at the moment, but for example its possible to get one at $160....
http://www.newegg.com/Product/Product.asp?Item=N82E16814133148
I got that card for another build im puting together, and it came with everything except a PNY labeld box... the adapters wires and drivers came with it. though none of that is nessessary, in case any of u were wondering.