I currently have a GTX 460 1GB that is performing decently, giving me around 40-60 fps in high settings in Skyrim and 30-50 in Guild Wars 2.
BUT my biggest pet peeve in the world of gaming is bad anti-aliasing and with it maxed, these games take a major hit with the GTX 460.
If I turn on ENB in Skyrim, then I lost about 10fps.
I want to upgrade to something preferably under $200, that will allow me to max out AA or use whatever new AA is out there without losing much framerate and still play with at least 40fps
However, my current resolution is only 1600x900.
My PC is a Phenom quad core with 8GB RAM.
FPS in guild wars 2 won't change. I'm using a GTX 660 and getting exactly same FPS. It's poorly optimized so you won't see much performance gain.
GTX 660 offers way better performance in Skyrim though. I'm playing skyrim at about 80 FPS at 1080p at ultra settings with HD texture packs and with 12 Graphics enhancements enabled.http://www.anandtech.com/bench/Product/660?vs=542
Here is a Little comparison so you'll get the idea.