it's definitely different when the person is in the car more often. i tend to drive whenever we go somewhere together. so i need to approve of whatever cars we get. she has to sit in the passenger seat and i'd like my wife to be comfortable, so i'll let her give her opinion and i will most likely take it into consideration when getting a car....
with that being said, i have my pacer, which she absolutely hates. hate hate hate... but she "allows" me to keep it/do whatever to it... because she is never in it. i use the quotations because in regard to that type of vehicle (rare use, collector car, sports car, whatever) i will get what i want, whether she approves or not.
i will also admit that even that type of car, i still want it to be a car my wife likes.. after all, i do love cars, but i recognize that cars really are just a way to "present" to the members of the opposite sex... for that reason, i have the morgan... she likes that one.