Vehicle: 1972 280SE 4.5
Results: 8.5-10.5MPG city/mixed, 13-15MPG highway (13 if I do 90-100, 15 if I do 70-80)
Driving Conditions: With the 8.5MPG mostly city (5% highway), with 15MPG that's extrapolated pure highway when comparing a tank I got 13.5 on with what it would have been had I not done 30 miles in-town.
Comments: I drive it like it was stolen. It pings lightly on 93 octane, so I never use less. High-compression heads from a 3.5 give me about 10:1 compression and it screams on the highway. If I floor it from a stop to 90, I can watch the needle go down. And I always do.

Non-MBs:
Vehicle: 1992 Jeep Cherokee Laredo
Results: 16.3MPG last tank
Driving Conditions: Mostly highway (95%), that was commuting to and from work.
Comments: It had the potential to be higher, but I do like to burn rubber with this 4.0 every now and then. It's very "torquey".

Vehicle: 2001 Chrysler 300M
Results: 21.2MPG this tank as of Friday on my way home from work (computer's readout is very accurate, I test it regularly)
Driving Conditions: Mostly highway (95%), also commuting to and from work.
Comments: City driving REALLY kills mileage on this puppy. I can be getting 24MPG average going just to and from work, but one trip into downtown and poof, I'm suddenly 2MPG lower. The trip to and from work also includes a 1 mile steep mountain road (on the way in) up which realtime mileage reads as 4MPG. The same hill on the way home is less steep, and I get around 10-14MPG going up it over 2 miles.

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Back in the saddle - 1972 280SE 4.5