I prefer AMD to Intel....
First, Intel is more expensive than AMD
second, Intel isn't very good for overclocking

but from what I've read from Computer Magazine, using benchmark software, Intel processor performance is better than AMD...(but I think it is because the price->2 intel processor can buy 3 AMD processor)

But actually if you like to change your processor often, you better use INTEL because from pentium 4 until core2xtreme using the same socket(LGA775), AMD uses many different socket(I can't remember it)