I'm going in June and I plan to take only a S110. It's small and pocketable. It will be the first vacation I haven't taken my 40d which is something. I'm quite over lugging gear on holiday... sometimes I was so over it I would leave it in the hotel room!
So yeah, to add another perspective I'm taking a small compact!
I know the feeling. I always brought my point and shoot (then a SD800 and now a S95) along with a waterproof enclosure so that I can safely use it on the water rides. On a ten day park hooper Disney World trip, leaving the DSLR in the hotel room felt like a vacation from a vacation.
However, I freely admit, that on such long trips, there's been plenty of times when I just wander around and take pictures of whatever looked interesting. That's when having the DSLR really came in handy. And that's why I always use the option of parking the DSLR stuff in a coin locker --- having the heavy gear near by is enough to forget all about it and relax.