My best and worst are covered by one car....my 1985 Pontiac Grand Am.

Best? 35 MPG, handled incredibly well on back roads, (DON'T tell me how fast I'm going, I don't want to know....), and was comfortable on long trips. (FT Hood-Mass, about 2100 miles, in 28 hours)

Worst? Ate brakes, (rotors and pads every 3-5k), went through alternators like mad, (9 alternators over the life of the car), and had to rework the head twice in one 20,000 mile timespan.

runner up for both? A 1980 Ford F-100 nicknamed the Yellow Peril. Take a bone stock F-100, and put a highly modified V-8 under the hood. It's never a good thing when you encounter lift while driving. Went through gas and clutches like the Grand Am went through brakes.

Current vehicles?

A 2004 F-150, great work truck, 4x4 and can haul a lot of wood.

A 1996 ford countour, which will wind up as a stealth rocket (I figure I can get about 200 hp out of the stock engine w/o a turbo)

and LOH's car, a bone stock 2002 Ford Taurus.