We went over spring break last year. Here's what I learned....
Stay with Disney, even if you cant get a discount (which you probably wont). We stayed at a downtown disney (nondisney) resort. The service and transportation were a huge pain in the neck. Disney knows how to take care of you even when they dont have too. We found everyone else totally uninterested in keeping us happy, because they were all over booked (hotel, planes....) and didnt need our business.
Book your tickets through the airline that will actually be flying you. We bought tickets through United, but were actually on USair planes. It was a huge pain to consider being bumped or getting on standby for an earlier flight and such. Even checking in and bags was a hassle (aiirved with our United tix at the united counter, stood in line only to be sent over to USAir.....)