After watching this same question for the past few years its very interesting to watch the results (my choice, which is usually price/performance)
- 2007 (based on company road maps and some tech sites) AMD
- 2006 Intel
- 2005 AMD
- 2004 AMD
- 2003 Intel
- 2002 Intel
But as Adam said, Businesses always go with Intel, Gamers love AMD. If you are looking at portability as in laptop/notebook, it's been Intel (because of centrino - the 3 headed processor, graphics, and wireless monster), but AMD is getting much better at their battery life, mostly because AMD bought out graphics card powerhouse ATI.
My best advice, forget this dilemma and just get a Mac, the software is designed around the hardware so it's more reliable and most efficient. (although Macs would be insane if they had an AMD chip)