If you stay at a Moderate or deluxe, you'll have a fridge in your room,now. It's a big plus, IMHO.
I second the water! Even if you aren't a water drinker at home, having water on hand in the parks can be a great thing, especially if you are going to be using a stroller. It just isn't a great idea to live off of soda the whole time you are there. If you won't have a stroller, then it might not be worth lugging around more than one or two bottles a day. You can also bring a few cans of soda or something with you and save money by drinking water with your meals but soda between meals. Disney will give you free ice/ice water at any place that sells drinks for free, but bottled water will taste better. There are also water fountains and sinks you could use to refill bottles.