First: An old working refrigerator full of beer.
Second: An old stereo (not some cheesy box). I have an old Sansui with some studio monitor speakers mounted to the wall.
Third: Decent lighting.
Forth: A dart board in case you run out of work to do on the bike.

Now you are ready to purchase a lift, tools, etc... to work on the bike. Without the refrigerator and stereo, I would spend little to no time in my garage!