We have both XP and 2000 in our office.
Both work great!
I use 2000 on my laptop and its very stable ... but when I go to the Platinum Crews' computers that have XP ... there are some very cool features.
Here is a testimate -- one of our hardcore MAC designers recently stated that he is really starting to like XP. (we do not have mac's in-house and all the designers are forced to use XP .)
Personally ... I am looking for an excuse to upgrade my laptop
