As a follow-up to my last post, here are a couple utilities to aid in cleaning out the crap from XP:
My Dad told me about this one: Startup Inspector - user friendly alternative to msconfig. There is a "consult" button that goes out and pulls back info from a knowledgebase about known startup items, whether they are good, bad or ugly.
And a co-worker told me about this: Crap Cleaner - Cleans out the crap from your registry, temp files, cookies, etc. Knows about different browsers, etc.
So, with a little bit of regular housekeeping using these utilities as well as spyware scanning (ie. Adaware, etc.), virus protection and Windows updates you can keep your XP machine very happy and running lean and mean.