For World of Warcraft the 750Ti is a better card. For most other gaming the 260X would edge it out a bit. Since i play a lot of WoW, i went with the 750Ti and i'm happy with it.
Last I heard it was Feb.1st 2012, but it's still rumor. Also check out the old articles about Nvidia vs. ATI in graphics for Blizzard games (WoW,SCII), Nvidia usually wins by a good margin. It's worth the research on a big $$ item.
I'd probably put a 5670 in it. The 300w power supply can handle it and it fits in the case.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102930
2- 5770 GPUs will use 150w-201w in crossfire. The coolermaster and the corsair would both be able to power your system. If you haven't bought your PSU yet, then get the Corsair.
http://forums.atomicmpc.com.au/index.php?showtopic=264
Not what i'd consider truly budget, but the Coolermaster Storm Enforcer is $90 and free shipping($80 with rebate)
http://www.newegg.com/Product/Product.aspx?Item=N82E16811119240
The Lian-Li Lancool First Knight only has one 3.0 USB front port, but it's $60 with free shipping...
"Let us know what you think about this new version!" How many times do we tell newbies "If it ain't broke, don't fix it" Well congratulations, you tried to fix something that wasn't broken and you made it worse.
Excellent article, also worth a read is this one by hardware secrets.
http://www.hardwaresecrets.com/article/How-to-Discover-Your-Power-Supplys-Real-Manufacturer/370
When i want the best power supply for any system i'm building my first choice is Seasonic.
Upgrade the power supply (Seasonic,... etc.)
http://www.jonnyguru.com/
http://www.hardwaresecrets.com/page/power
Smaller, more efficient cooler.
http://www.frostytech.com/
http://www.hardwaresecrets.com/page/cooling
Case reviews.
http://www.hardwaresecrets.com/page/case/15/1
Maybe 2x4 GB...
You blew my "dirty power" theory out of the water. If you pinpoint what caused the problem, if it was 2 faulty power supplies or whatever, please let us know.