For interest - got the Logitech G25 yesterday. It is awesome! Prior to this, I have been playing GT5 for some weeks now - managed to get all the way to the Ferrari with the normal controller! would have been much faster/better with the wheel.
GT5 I find is very realistic.
I found GRID is much better with the wheel (rubbish with the controller) - but it is very frustrating at the same time.
Just not as good as GT5.
Ben / Phil - thanks very much for the information guys.