Check out the Orlando Hotels & Attractions boards and you will find many threads on this topic.
To answer your question, we rented a pool house in Windsor Palms this past Feb. and we loved it. We were able to access Disney through a "back entrance" (Sherberth Rd.) and were on Disney property in about 7-8 minutes with very little traffic. Driving to the parks was actually as quick or quicker then using Disney transportation. It was awesome being able to put the kids to sleep in their own bedroom vs. trying to get a 2 and 4-year old asleep in one room and having no adult evening time. Also loved being able to eat a quick breakfast before going to the parks. We saved a ton of money and had a great time. The only downside to me is that there's no maid service during the week, so I did have to spend more time cleaning up then I like to do on vacation (that's where I lost a little of the onsite magic).