Consumer reports 10 best for fuel mileage.
 

Rank Model tested CR Overall mpg City mpg Highway mpg 150-mile-trip mpg
1 Honda Insight (manual) 51 36 66 61
2 Toyota Prius 44 35 50 48
3 Toyota Echo (manual) 38 29 46 44
4 Honda Civic Hybrid 36 26 45 44
5 Scion xB (manual) 32 25 36 37
6 Scion xA (manual) 31 22 38 39
7 Toyota MR2 (manual) 31 25 36 34
8 Mini Cooper Base (manual) 30 23 38 35
9 Mazda3 i (manual) 30 21 42 36
10 Scion xB 30 23 37 35

Excludes the deisels. All the VW TDI deisels would go between 2 and 3 on this chart.

Gassavers Frapper
 

My 1991 Honda CRX would come in third for overall mpg, that's nice to know, and it's auto, and it's got some crappy mpg wise features I should say too. My last year's soc teacher got an xB and says it is nice on gas, kinda small though.