'90 300D 2.5 Turbo (OM602 5-cyl 2.5L motor) 32-34mpg highway. Got 36 once, but that was on a very tail-windy day
Averages about 30-31mpg in normal everyday driving.
'98 Volvo S70 GLT Turbo (2.4L 20-valve 5-cyl) gets about 24-25mpg on the highway. It's the dad's car, and he commutes about 70 miles round trip per day in it, so he does about 80% highway driving.
'91 Volvo 240DL wagon (2.3L 4-cyl), the doggiemobile, gets about 26-27 in everyday driving. It has gotten 30mpg before on the freeway, but that was while driving 55-60mph. It is a 5 speed.
'92 Ford F150 (5.8L V8). Need I say more? Best I think I've seen out of that POS is 15mpg. Mostly averages around 12mpg, seen it get to 10 or worse mpg while doing work truck errands around town.