I don't have a car and I rarely transport my bike by car. Considering how often I lock my bike up around the city, quick releases are a liability and a hassle. That is why I got rid of them on all my bikes. Given my circumstances, quick releases are serve no purpose when I can use the same multi tool I always carry to remove my wheels if I need to. Yes, theives can use the same tool, but so far after 2 1/2 years they haven't.

I think it was Sheldon Brown who said saddle theft wasn't a problem until the advent of the quick release seatpost.