The Beatles: Rock Band Special Value Edition $80 @ Amazon
Amazon Canada has an excellent price on the Nintendo Wii game The Beatles: Rock Band Special Value Edition. It's only $79.98!!
This set includes the game itself, and the regular Rock Bad instruments (drum kit, guitar, microphone).
I did find a little article on Joystiq though, if you want to read it before forking out the cash. It's about how this value bundle contains the instruments from Rock Band 1 rather than RB2, so take that into consideration.
I think this would be an excellent pressie this Christmas.
Remember, as this is over $39, you get free shipping automatically.