If you can get the Cooper D for the same price as a petrol Cooper I'd recommend the diesel any day.
I've done near;y 6k since I bought mine at the end of December '07 and it's fantastic. I had some lunatic try and pull away from me onto a motorway today in a Mondeo ST TDCI. They have something daft like 400nm of torque but through the gears I kept up with it up to errr, high speeds
It's very economical and handles very well... lots of fun.
At the end of the day, even if you don't drive much it will cost you less than a petrol in terms of tax, fuel and probably insurance so there's no contest if you ask me. The 1.6 petrol is supposed to be lacking on torque compared to the old model and you must have to ring its neck to go at all fast in it... nevermind overtake on the motorway (which the Cooper D really excels at).
