PJ, your question was about the difference between the two products. It was a
pretty open-ended question, and you are going to get answers from all over
the place.
I assume that you are aware of the additional feature and function sets that
are well explained on the product website. It all comes down to how well 2000
serves you now and whether you need, for example, native XML, smart tags,
productivity shortcuts, etc. 2003 is loaded with features. I believe you
might even be able to evaluate it at no cost, so that's probably you best
option toward making an informed decision.