Choose your processor based on your intened use:
Athlon chips are best for Office type applications, and are much faster with programs of this type. Athlon XP chips are only average for gaming, Athlon 64 chips are currently best for gaming.
Intel P4 chips perform best with gaming and video editing. P4 was best chip for gaming until Athlon 64 was released. Performance wise, Prescott chips are not worth buying until they hit at least 3.6GHz. At the same speed, Northwood chips beat Prescott chips (this reverses at about 3.6Ghz, assuming you can get a Northwood to run that fast).
