I have had my eyes on the 650 Ti Boost Superclocked by EVGA and the HIS 7870 Ghz Edition, but Im not sure wether or not the 7870 is worth the extra 20 or 30 dollars. Can someone please clarify?
7870 would be worth it, besides you should be able to find a 660 for less than 200, as for 7870 vs 660 they're pretty damn close, but i'd give a slight edge to a 7870
I has a similar question so this may help, also see reply from ragingh4vok
https://teksyndicate.com/forum/gpu/msi-gtx-660-twinfrozr-iii-oc-2gb-or-vtx3d-hd-7870-black-ed-oc-tahiti-le-2gb/147333
The Radeon HD 7870 performs a bit faster than Nvidia's GeForce GTX 660. However, a recent price drop to $190 earns this AMD card our sole recommendation. It's a serious gaming board capable of playable frame rates at high resolutions. Currently, the 7870 is your most powerful option south of $200
http://www.tomshardware.com/reviews/gaming-graphics-card-review,3107-4.html
I tend to take a lot of Tom's stuff with a grain of salt, but the 7870 is a really good card. It will destroy a 650-Ti, especially if you consider OC headroom.
Here's a 7950 for $200 after MIR. It's definitely worth the cost for the performance you'll be getting. It'll chew up the 7870 (as well as those other aforementioned cards) and spit 'em back out. It also comes with 3 free games.
http://goo.gl/1NLAFQ