Most artists don't want to be hackers or take the time to fiddle endlessly with their machines. I'd say go for XP for stability and ease of use. Another factor which has not been mentioned but can be very important for artists is XP's thumbnail view in Explorer. Until XP I hated Explorer and only used substitutes, but now I wouldn't be able to live without it. The value of being able to SEE what you've got cannot be underestimated.