For a CPU, go AMD! They're faster, less expensive, better for most applications, and provide a better upgrade path than Intel...
That said, there have been compatibility issues with certain Athlon motherboards and the Creative Labs SoundBlaster Live!, however the Live! is not the end-all, be-all of audio cards, and many if these "issues" have been dealt with by the motherboard manufacturers. The SB is a very good product, but it is dated, and the Turtle Beach, Phillips, and Hercules current generation cards offer better sound (fewer features though, except possibly the Herc.) without fear of compatibility issues. They are more expensive than the Value edition of the Live!, but less so than the Platinum version.
There also have been compatibility issues with some digital video editing cards and some Athlon mobos, but these cards also have issues with Intel-based computers. This should only be a consideration if you intend to create or edit DV movies with a DV camera and your computer.
I know of no other real compatibility issues with current AMD processor-based computers and any commonly used current hardware...