Things with 2 wheels can do stuff things with 4 wheels can not.
Its my personal opinion that dirt bikes are far more fun and can promote a much higher level of excitement. Do you drive a car to work or school everyday? Feel a bit confined and is your movement limited? This is what I mean about things with 4 wheels.
Of course, you should always consider the proper safety precautions, understanding of your own limitations, and a basic understanding of physics, etc and so on.
When a Banshee does a wheelie, its looks pretty cool.
When a dirt bike does a wheelie - even the chicks dig it.