Mine gets washed once a month, whether it needs it or not.
Pretty neat little car for running around town. Zips around, fits in small parking spots, etc. Lifetime MPG to date is 47.1. For long distance highway driving it could use a bit more legroom.
I agree on the idea of a wagon based on the existing Prius chassis. Square off the back and make it a couple inches longer. Something like that would make a very utilitarian vehicle. They have shown a prototype of a Prius pickup. Surprisingly, that looked pretty much useless, not enough real world capacity.
The major drawback to driving a Prius is that people automatically assume that you are a leftist crackpot. Putting a couple "Support our Troops" bumper stickers on the back confuses the hell out of 'em.