I can vouch for the Energizer e2 Lithium batteries as well. They are pretty amazing.
I used to carry 3 to 4 sets of batteries for my digicam when I first got one (in 1997). I have a digital camera bag that has a little "bandolier" for AA batteries inside the front flap. I would keep 1 set of 4 in the camera, 2 sets in the bandolier and 1 more set rubber banded inside the bag. This was just about enough to get through a day (200-300 shots for me).
At that time I was using Ni-Cd rechargables and they were heavy, and had only slightly better use time than alkalines.
I then upgraded to a newer camera in 2000, but kept one with AA batteries. This time I went with Ni-Mh batteries, and they have continued to improve over time. Nowadays, Ni-Mh batteries have about2.5 times the energy capacity of the first ones I got in 2000. They are VERY good. They do have the drawback of losing their charge as the sit for a while (days or weeks). I kept the same camera bag, but had enough charge, that I did away with the 4th set of batteries. So I was only carrying 3 sets (1 in the camera and 2 in the bag's bandolier).
I just got a new camera earlier this year (a Canon PowerShot S3is) and it again uses 4 AA batteries. At the time, I also got a set of the Energizer e2 Lithiums. I've been using the lithiums for about a month (about 200 shots total in that time along with 15-20 minutes of video - I don't take nearly as many photos when I'm not on vacation).
They are still going strong.
I think for normal use at home, I will still use rechargables because I can easily leave a couple of sets of Ni-Mh batteries sitting in the charger being kept at full charge and grab them when I leave the house, but for a week long trip to Disney, I would say ~$12 for 2 sets of fresh lithium batteries is well worth it so that I don't have to carry the heavy rechargables and the charger.
One thing that amazes me is how light the lithium batteries are... it is another benefit.
Since the S3 is also so good at shooting video, I've also replaced my camcorder at the same time, so I am down to one medium sized bag (about 5 inches by 4 inches by 8 inches) to house all of my photo/video equitment for the trip - including a 100GB portable hard drive to dump photos and video to along with its AA battery pack so I can even use it without my computer.
This has been very long winded, but there is somewhat of a reason

...
if you look through my post, the biggest recommendation I can make is to get a camera that takes AA batteries. It gives you the most flexibility (and with the energizer e2 lithiums, the absolute longest run/shoot time). You can use value-minded Ni-Mh rechargables, you can use ultra long-running lithium disposables, and if you are in a total pinch, nearly every concession stand or souvenir shop in the world - both Disney and in general - will have AA alkalines that you can use in an absolute emergency.
Ted