Guess its a personal preference... sometimes i do like alot of bass, sometimes i do like less bass. i think a mixture between the two is always good.
People say to me " why do u need bass in your car" my reply is, if you like your music, and went to a concert, would you be very disappointed if there was no bass kicking through out the room. not that im suggesting bass to blow off your windows. There is a level of bass that is just stupid for driving, but i think that consists of 4 or more subs which usually suggest show car.
Although i would not mind having that many.. and could turn it up and down when ever i pleased.