I purposely switched from AMD to a P4. When not in use my pc processes Seti work units. My AMD 1.4Ghz averaged 7h 30m per work unit, my P4 2.66Ghz averages 2h 50m. There is currently no AMD processor which can get close to that time.
Benchmarks only tell half the story. How the CPU performs in real life is more important. For things requiring calculations, such as Seti or spreadsheets, then the P4 will be the choice. For games, then the AMD will be the choice.
I play a lot of system bashing games but decided to opt for the P4 anyway. The reason being with my Ti4200 I get over 11000 using 3DMark2001 without any overclocking which is more than adequate for any new game. Looking at this month's PC Extreme magazine I see the top benchmark for a Ti4200/AMD is 10569 with a XP 2000+. It is possible to overclock and get up to 16000 with an AMD/Ti4200, but is hardly worth it. Running UT2003 at 1024x768 with all the extras switched on I have no difficulty getting a 90fps average.
Overall for a satisfactory games performance and the required speed I need for Seti, the P4 was the right choice for me.