Which do you guys prefer for your desktop processor?
I prefer AMD, since they are way better CPU's for gaming, multimedia, and just better overall.
Also, AMD was first to release a 64-bit CPU, and it is backwards-compatible with current Windows and software and games! Also, it is considered, by many, to be the top of the heap!
I, personally, don't like Intel, because of their push for dominance and monopoly of the market, on the CPU side.
However, Intel does make good CPU's for the laptop market, although I hear that AMD is releasing a newer 64-bit socket 754 processor for the laptop that has very low voltage requirements.
What brand do you prefer?

AMDs offer more bang for the buck, run cooler, and are generally faster than their Intel counterparts.

The only problem with the AMD line is that the chips are notoriously fragile and are not shimmed. If you install an AMD chip, you must be very, very careful not to crack the chip, as that can lead to malfunctions.