I agree. Office XP has some really nice features. On the consumer level, however, it probably isn't worth the price if you are already running Office 2000. At this point, I'd suggest waiting for the next version of Office. It will be released next year.
Of course, if you have come across a good price on XP (student discount, etc.) and don't mind parting with the money, I'd say go for it. I definitely prefer it over Office 2000. Smart Tags are very neat. And the new Cut and Paster options save me an enormouse amount of time.