Mossberg Persuader with duck loads, a Glock .40, and a locked garage do the trick for me. If we hear noises coming from the garage I grab the Glock to investigate. GF backs me up with the Persuader, and she is really good with it (I would not want to take her on with only the Glock).
Bike locks provide almost no deterrent to the professional - they are OK for keeping honest people honest. I never ever leave my bike(s) unattended outside of my garage. When traveling, I sleep with it. I will park the 12GS at work since it is so fugly no one would want to snatch it.
my favorite bike - R1200GS