One of my most ardent hobbies is motorcycle collecting. I buy and sell three or four bikes a year. Cruising the various classified sections on the motorcycle internet forums can reveal some amazing deals. If you buy them right, usually in the fall, you can ride a bike for a year or two and sell it for what you paid. Not a bad hobby.
This is the current collection.
2007 BMW X Challenge
2007 Sizuki DL650 V-Strom
2004 BMW R1150RSL
2004 Honda VFR w/ABS Brakes
1987 BMW K100RS – M Sport
2001 Moto Guzzi V-11 Sport “Rosso Mandello”
Limited Edition  #89 of 300
1972 Honda Trail 90
You can see all the bikes that have come and gone over the years in the photo album
http://public.fotki.com/Rbertalotto/motorcycle/motorcycles-current/