I will not buy a camera that does not use AAs. It can save the day when in a pinch. If your camera takes a special battery, you will probably not be able to buy one at the parks. Even if you could, it would cost a fortune. They are usually around $50 from discount stores, so I can only dream at the price Disney would charge.
AAs also gives you many choices. There are rapid chargers that take 15 minutes, up to 2500 mah batteries, lithium disposables, etc. If you have the time, use a slow charger(8 hour or so) instead of a rapid one because you will get a more complete charge. The rapids go to about 80% of capacity while the slow go to around 95%. If you have the radid charger, remember to bring it with you in the parks. Makes a good excuse to take a much needed 15 minute break!
I have 2500 mah Energizers and usually get around 450 shots per charge with a slow charger. Be careful with lithiums and read your documentation. Supposedly they can damage some cameras and void the warranty. I doubt that will really happen, but better to be safe than sorry when talking about a $300-$1000 piece of electronics.