I would also highly recommend you get the newer composite tanks, rather than steel or aluminum propane tanks. The new tanks have translucent side panels that actually let you see how much propane is left in the tank. They're available in 10, 20 and 30 lb. sizes, however the 30 lb. size aren't designed for simple low pressure devices like stoves and heaters.
These tanks are not available in Canada. They have not been certified by the Government yet.