For low cost performance, I think AMD does offer a good platform. An AUS Crosshair mobo, 5000+ Black Edition cpu and 2 gig of ram can turn out a good computer for about $510. You can use a cheaper mobo and get the price down to less than $400 as well. It won't overclock as high as a top Intel, nor turn in the generally good game performance of an Intel, but it will cost less, a lot less if the Intel comparison uses their top end chips. Also, if you want, you can build on the new Phenom FX790 mobo for about $550 and have the ability to upgrade to Phenom, if AMD ever gets the bugs worked out with that chip.
A couple things to think about. I used to have a FX60 machine, which I gave to my son a month ago. When running a compatability test for Crysis, it scored near the top. Really, it was my video card holding me back more than the cpu. Thus a AM2 5000+ Black Edition that's overclocked should do fairly well with Crysis, at least according to the test that was released.
Second, though a lot of people get carried away about how great some of the top Intel machines perform, very few people actually have them. Check out the machine specs that people have and you'll find that the majority are not the latest, highest performing Intels. Its easy to talk about Intel's high performing chips being fast. Its another thing to actually to buy one.
That said, with the Phenom being such a bomb, I'm planning to build an Intel machine. Just waiting for the new graphics cards that Nvidia is supposed to release in Dec, though I might build now and put my old 1900 XTX in it while I wait for the new Nvidia.