I think of a biker as a person riding a Cruiser, often seen in black leather with tattoo's all over the place (stereo-type). A person on a 1000cc Gixxer will never qualify as a biker to me. He is a motorcyclist, or just one that enjoys riding a bike.
I tend to agree there. If you buy a big expensive bike, and use it for a towel hanger, you probably would not qualify as a "REAL" biker. I put about 1000 a month on my bike. I will take the car if it is raining, and I don't want to spend an hour polishing chrome :)