Don't want to cause any paranoia here but very often thieves will have another look after a while to see if you got replacements through insurance. I know from advice in community Police newsletters that this happens after house burglary so it may be worth beefing up the security ready for your replacement bikes.
I second this (as I've been a victim to it, 4 times no less)... if you can't beef up your security just try to keep valuable things out of sight when your not in, to stop them looking through the window and seeing the goods.
My last straw was when they kicked my door in, raided my newborn sons room and took my bike. So I replaced the door with a 16 bolt steel door and a wireless CCTV camera, that seems to have stopped it. I also started the services you see in my footer, if I can't catch them for my own crime I can at least make their life difficult.
On a side note if you've got a new bike, I've just finished a new site that shows you your nearest police registration events (here's
London).