personally i'd go with diesel. Im no machanic or car person but judging by how diesel is a very common fuel source (judging by my location) it is easier to find in those times when you may be low on gas.....i'll keep researching to find an MPG figure for the two But so far i'm not getting lucky....
my bad...
"Facts At A Glance
CAR: Toyota Avensis D-4D diesel range
PRICES: £15,545-£23,205 - on the road
INSURANCE GROUPS: 7-11
PERFORMANCE: [2.0] 0-60mph 10.3s / Max Speed 124mph
FUEL CONSUMPTION: [2.0] (combined) 51.4mpg
STANDARD SAFETY FEATURES: Dual front, side, and curtain airbags, drivers knee airbag, ABS, EBD, ISOFIX child seat fixings
WILL IT FIT IN YOUR GARAGE?: (length/width/height mm) 4630/1760/1480" -Yahoo! cars"The petrol burning Toyota Avensis 1.6 Valvematic can cover 43.5 miles" - carsession.com
Diesel- 51.4mpg (go with this. lol)
Petrol 43.5 mpg
uk.cars.yahoo.com