Had my bike nicked from my garage last year. It doesn't matter how much security you have, if they can work without being disturbed, they will defeat any security with the right tools.
Security which will have to be in place before I entertain the idea of replacing it with something nice will be either IP or GSM alerting PIR alarm system on motion in that space, The bike will also have one of these as well as it is no point having the best detection kit on the property if you can't track it once they ride off up the road.
http://www.integratedtrackers.com/GPSTrack/
The scrotes also have nowhere to hide in dark corners anymore, and will have to scale a 10ft high fence and defeat deadlocks whilst tripping a 500watt halogen lamp which doesn't just light up the outside of the garage, but also the hall and landing in the house - it turns night into day, and has done it a few times from Bats and birds @ 3am, but not a biggie as a trade off for peace of mind.