This is the first time i've built a pc, but I've decided to get the GeForce GTX 660 Ti as a graphics card because ill mainly be doing gaming, but there's the Gigabyte version and the Evga version, WHATS THE DIFFERENCE?
If you plan to overclock (or at least want to have the option to) go with Gigabyte as their custom coolers are better. EVGA, although the coolers aren't as good, provide better warranty (This is what I've heard). Both have good warranty though. The Gigabyte will run cooler, so its my pick, but make sure to weigh your options.
EVGA would be more of warranty, it is also a reference design. Overclocking would be quite limited in the EVGA card since it uses a blower style fan compared to an aftermarket cooler. Gigabyte uses a custom cooler and if I'm correct custom PCB layout. This will be better for overclocking because of the better cooling. Custom coolers usually are very quiet compared to the blower style fan used in EVGA cards. I would go with the Gigabyte one because I can't stand loud graphics cards.