I love buying the 5+ year old cars for under $5K with about 100,000 miles on them. My first car I bought after college was the original 1977 Toyota Celica 6 cylinder with just over 100K miles. This car was put on the market to compete with the hugely successful Datsun 240Z.
I would have never believed it but I drove that car until it hit 326,000 and sold it for $50 and it was still running.
Currently, like a few others here, I've been driving a my 1995 Jeep Grand Cherokee that I bought seven years ago with about 100K miles on it and the odometer just turned 268,000.
I almost went for the Cash for Clunkers deal but this Jeep has never had any engine or transmission work done since I bought it and it still runs strong and smooth... not bad for a $4800 vehicle.