Fush is right as far as sims go. PC racers with high modability are currently the benchmarks for sims racers, and make Gran Turismo quite arcadey.
My vote goes to GT regardless, simply because of it's accessability.
For arcade racers I am voting for Wipeout 2097/3 the greatest arcade racer, but if it must have wheels then it is Burnout 2/3, not many people realise that it is from a gameplay standpoint much better than the street racing games, though admitadly it does lack that street racing atmosphere that is oh-so popular these days.