I agree Stacy, it really depends on what you want to do. If you think you'll spend most of your time at the Magic Kingdon, then just for convenience, stay at one of the monorail resorts.
With little ones, you'll be making trips back to the hotel regularly, being on the monorail makes it so easy, and quick.
If you think you'll spend more time at the resort than in the theme parks, that changes what you might want. Lots of people rave over the Animal Kingdom Lodge and it has a zero entry pool, I think. There's storytelling nightly too. Other folks really like the family atmosphere at the campgrounds.
I think its best to decide what you want to do, then look for the resort that will accomodate you the best (for atmosphere, location, and budget). The good news is that your kids will have a great time regardless...it's Disney.