I personally like AMD for price/performance (ie value). Phenom II processors rock, a triple core 720 should suffice for gaming if on a budget, if not the quad core 955 is a great CPU (more of a future proof option than an actual need).
The i7 are the best CPUs, but their cost together with motherboard and DDR3 memory, may be too expensive. I don't feel anyone who does not use their computer for proffessional uses (extensive 3d rendering, video editing, etc) actually needs an i7, and you could use the money you save on a better graphics card if you intend to use the Pc for gaming.