I have a 2004 2500 Suburban w/4x4 and 8.1 litre. Live in rural San Diego County, California. Also drive a Prius for my 75 mi. daily RT commute. Get 12mpg in the Suburban and 40mpg in the Prius. I figure it balances out. The Suburban has to last me the rest of my life which I'm planning on being rather a few years.