AMD desktop CPU's completely wipe the floor with Intel's. They are more energy-efficient (even without Cool 'n' Quiet, although this certainly helps a lot), beat Intel at most tasks, and are generally cheaper.
Do not buy an Intel-based desktop PC. Notebook? Perfectly fine, assuming it's a Celeron M or Pentium M, but never a desktop.
Intel chips with hyper-threading might be better at multi-tasking than single-core AMD's, but the 64 X2's are far better and more energy-efficient.
AMD 110%.