New Nvidia GTX 660ti or the new GTX 580 (although discontinued, Fry;s is still carrying these cars for around $350.)
I've googled the answers, and some say its a dead even match..What are your guys thoughts? Just need explanation and straight answer on what to get as i plan to get one of them tonight.
Honestly for that price you should be looking at a sapphire 7950.
Out of the 2 you have given, the 660 ti is about 8% faster at stock with better power consumption, but has crappy overclocking potential and is neutered bandwith wise.
The gtx 580 can overclock better, but uses more power, it would depend on what manufacturer and it's cooling solution.