I tried to go green a couple of years ago, especially since my annual mileage dropped from around 20,000 to about 7,000 when I developed a pathological hatred of the M1.
So I went from a 4-litre Jeep Cherokee to a Honda Jazz
, and it was the best move I ever made. The Jazz is a Tardis - holds more than the Jeep did - costs a quarter as much to run and is a doddle to drive even in traffic with the CVT-7 box.
But it probably isn't ideal if most of your time is spent on motorways - it cruises happily and quietly at illegal speeds (or it would if I did
) but fuel economy tails off as the engine has to work harder.
I like the idea of the Prius but you pay a lot for the technology, and I'm not sure how eco-friendly it really is with all those batteries. The great thing is that it recovers potential energy going down hills, instead of burning it off as heat in the brakes. But, from what I've read, a decent diesel is just about as economical overall and costs less.
Having recovered from the 4x4 phase, I'm not a fan of them unless you really need that sort of vehicle. They don't have as much room inside as a normal car because of the space taken by the drive-train, and although the high seating position gives good visibility it doesn't help stability or aerodynamics. For something with loads of space, decent power, good economy and a sensible price, I'd go with Dabhand's suggestion of an Octavia - same basic car as an Audi A3 or VW Golf, but bigger, cheaper and (according to J D Power) more reliable.