I've been using mine for a few weeks now and I have to honestly say that there hasn't been a second when I've regretted it in the slightest. Yes it was a lot of dosh, yes it's tough wandering round the shops with my friend and she's buying stuff and I can't - but no way would I had it back now!
I had the chance of buying a 2nd hand 20D at the point at which I was making the decision, and plumped for the 30D anyway. Several reasons - just those few more features made it a better bet I felt, and also I really REALLY wanted a brand spanking new camera all of my own!
Out of interest, a friend who was at that point using the 350D swapped to the 30d just a week after getting a good look at mine.....!