I'm quite experienced with booking flights, and hotels on-line, but when it comes to booking rental cars, I'm a bit of a novice.

I've checked Hotwire.com, and got some initial prices, but I was wondering if anyone could recommend any good web sites where I can go to compare rental car prices (similar to Orbitz for Flights or Travel Web for Hotels)

I'm travelling to Minneapolis and am looking for a rental car to pick up March 21, and drop off March 24 in the morning.

Looking for either a Premium or Luxury car, and unlimited mileage.

Thanks in advance for any assistance you may be able to provide.