But CS3 only works with Vista. Some people want to stick to XP because Vista gives too much system overhead (and eats away RAM) largely because of its "premium content" protection system.
A Cost Analysis of Windows Vista Content Protection
I also heard rumors (shockz!) that Vista degrades your own photos behind your back because it considers them as "premium content". Patrick, where is that DPReview thread about it ??

I heard that there isn't so much difference between CS2 and CS3.