The Concern for the PSU, while noble is probably not necessary but... probably... If you want a new PSU go for ANY Seasonic PSU, otherwise look at the reviews and they'll tell you if it's good or not. Rosewill, EVGA, Corsair, and Seasonic are the best guys out there.
http://www.videocardbenchmark.net/gpu_value.html
^This is the best place to get a general idea on if it's a good deal or not (just for reference.)
Circle is said by some to be untrustworthy at best using cheap parts and claiming it to be "80+" certified and whatnot. Stay away from them at best.
That's my thought on them, same with many other brands such as Diablotech(seriously, Who names their company after Demons?)
GO for the GTX 660 if at all possible, It's faster to say the least. Unless you find the 750 Ti 2GB for $120, the ASUS GTX 660 DCUII for $150 ($120 with rebate) is your best bet.
What is your budget? PCpartpicker.com can help you choose too.