On my '02, I got a tow hitch from Coastal and a Saris T-Rax bike rack. It makes a pretty solid looking block of metal back there. Not much change in MPG without a bike, either.
I did, however, get tagged by a big pickup truck in a drivethrough after the install, and he got more damage (I think, hard to tell on his rusty bumper) than I did on my rack.