I did the big wheel thing once on a Golf TDI I had and regretted it straight away.

It looked nice and gave more grip but was skittish and killed the fuel economy.

I have never gone back and got big wheels again on any car I've had and they are so shit. Look at F1 cars, they have tiny wheels and massive tyres.

[edit]

14" steels below, the car drives best on these and I reckon they look brilliant