In no particular order...
1. You change firmwares more often than you change your underwear.
2. You have a separate PCI IDE controller filled to capacity for all your optical drives.
3. You have discs pinned to your ceiling ( http://dwh1002.homestead.com/files/050.jpg )
4. You post threads with names like RICOHJPNW11 - 451S GSB6 vs. 451S @ 832S VS0A
5. You have several shortcuts to K-Probe all around your desktop and menus.
6. You've already tested dual layer DVD media (as of 8/1/04).
Umm... I can't think of anymore. Feel free to add.