We like having a rental car to go off site for groceries, malls, explore central Florida, beaches, etc. It must be nice for those of you that have the ability to drive rather than fly when visiting WDW. We don't use the rental car to go to MK at all; it is much easier to take the bus and be dropped off by the front. I would say that we use the buses even with a rental car 50% of the time for the other parks.
The prices for rental cars went up dramatically after 9/11. For the same time period and same amount of car, the prices this year were over $200 more. I refused to rent last month because I think these rental companies were taking advantage of the situation and raising their prices.
This past trip was the very first trip I saw any problems with the bus system. We had one bus break down on us and one with no a/c and a very long wait when MK closed. I don't know if cut backs had anything to do with these problems.
I would like to see more boats to Downtown Disney, myself!