Ground anchors are good. I have mine fastened down with the break type security bolts, just type in "ground anchor bolts" into eBay, they are about £4.
The most important bit is the lock and chain, I use the locks and chains from http://securityforbikes.com/security-chains.php
They are impressive bits of kit and the service is great. I use the 16mm chain and squire lock, no one is getting through that. If someone really wants my bikes they will probably just mug me .....
The reason for using this lock is most of the big brands lock and chains are cropable in under 30 secs even the gold standard sold secure ones. If you watch the link below you may feel like I did. I have probably £5000 worth of bikes so spending £200 on locks and chains seems like a good idea.
I know we are insured, try getting bike cover on your home insurance after you have made a claim, not likely. You then end up paying or separate insurance that as a rule of thumb is £10 per month or every £1000 you insure depending on area etc. Most of you have bikes that cannot be replaced by going to a shop so we have to take security more importantly.http://m.youtube.com/watch?v=Cpf35C7wu6 ... pf35C7wu6Q