I want to know if I can play games like Battlefield 3, newer Call of Duties, all of the Crysis's and maybe Crysis 3 when it comes out, Skyrim, GTA IV, and more on maxed out, or atleast high, settings.
Ram: 8GB of DDR3
Graphics Card: SAPPHIRE Radeon HD 6870
Processor: Intel Core i5-2500K 3.3GhZ Quad Core
Probably. Assuming it's around 1600 x 1000 res or less w/o max anti-aliasing and anisotropic filtering, etc. GTAIV, CRYSIS and BF3 may be pushing it though. Might want to look into getting two video cards.
no. bf3 will run on high not max settings. gta 4 will not max out due to the drawdistance needing 1.5 gigs of vram. call of duty any version yes they will max out with 60+fps minimum crysis 3 will likely run on high but not ultra.
to max out everything you will need a gtx670 (out next week if tweaktown is to be believed) but the 6870 will run everything you have listed on high but not max em out...