I still loved GT3, 4 was a bit of a drainer, think I switched to Xbox after that. I enjoy Forza but don't play it much anymore. I've always been into drifting and Forza do it well, used to do multiplayer with a heap of mates, that was good fun. Dabbled with wheels a couple of times but never commited to a decent set up. You need a whole games room for that otherwise you have to pull the eyesore apart every time you're finished with it or it turns into a kids playground/clothes horse. I don't have the space so just deal with controller.
Unfortunately every time I have half an hour to kill, anything I put on wants to do an update that takes longer than I can be bothered playing for. I still play Skate 3 fairly regularly though.