I have two gas eaters. I know, it's not very "green" of me, but I'm an enigma.
A Lincoln Navigator, which I fill up about once every two weeks and a Cadillac Sedan DeVille, which I fill up about once a week. So, all-in-all, about 120-130 gallons a month.
"I got news for you. If it wasn't for the toilet, there would be no books." --- George Costanza.