From my research, Intel will offer a better chip; lower voltage, lower heat, can be overclocked (thought not as easily or as much depending on who you ask, I have no experience there). AMD is a bit further behind, but you can get a chip that may clock a little slower, but when you're comparing a quad core with each core running 3.3 ghz vs. a a quad core with each core at 3.0, do you think you will notice the difference? If you think you will, is that difference worth the substantial amount of extra money you'll pay for an intel?
AMD is a better bargain. Unless you're really hardcore and want to drop alot more money on a high end i7 and get yourself some triple channel memory, don't bother.