Although AMD systems can run OSx86, generally speaking, you're better off with Intel for Hackintoshing. Apple uses Intel CPUs (and I believe Intel chipsets, although I'm not 100% positive that's true of all Apple's models) in all its post-PowerPC computers. This makes it easier to get OSx86 running on an Intel-based system, all other things being equal, since you don't need to worry about CPU compatibility and you're more likely to get a chipset that's similar to one that Apple uses.

If you insist on going with AMD, you should be aware that you'll need to run a third-party kernel and you'll probably have to run a program that scans all your applications for Intel-specific code sequences and patches them so they're AMD-compatible. (Some kernels for 10.5.x include run-time patching, but AFAIK no such kernel for 10.6 has yet been released.) AMD and nVidia both make AMD chipsets right now. I'm not sure which is more likely to work well. I've got a 2-year-old AMD system that runs OSx86 (iPC and Hazard) reasonably well, but the on-board video doesn't support QE/CI, so I've added a PCIe video card (and I still haven't gotten QE/CI working in 10.6). Overall, I had a much easier time with a laptop based on an Intel CPU and Intel chipset. IMHO, you're better off going Intel, even if it means you must get a slightly slower CPU, smaller hard disk, or otherwise cut corners to meet your budget.