Here are some categories I've thought of:
Star Wars: Speeder bike or custom swoop
Star Trek: U.S.S. Defiant
Car, sensible family-type: Subaru Legacy, current design
Car, super: McLaren F1
Car, muscle: Cobra
Motorbike, retail: Something simple like a Yamaha Virago
Motorbike, custom: one I've designed based on a Model A pickup truck
Motorbike, fantasy: Tron lightbike

SUV-type: Range Rover
Ok, that's enough for now. Feel free to add as many categories as you'd like.