Part of me thinks a medium grade U lock and locking skewers is plenty. Reasoning is, casual thieves (meth heads, tweakers, joyriders) won't bother with a U locked bike, any U lock, they'll just move on. There are plenty of cable locked bikes. And the pro thieves are looking for more valuable bikes to use their grinders on.
Completely wrong, I'm afraid.
A lot of u-locks can be opened with simple leverage - a long piece of wood or metal scavenged from a skip of fencing - and even bottom feeder thieves know this. (
http://www.bikeforums.net/commuting/...k-pretzel.html) And they're as likely to be carrying the jack needed to defeat high quality U's as they are anglegrinders or heavy bolt cutters. And anglegrinders eat most u-locks anyway.
Part of me thinks a high grade U lock AND a heavy chain is needed. Reasoning is, the bike will be there every day so eventually some pro will decide he wants it, maybe just a little score on a slow day when no $3000 bikes are ripe. Only chance to dissuade him is to force him to make four cuts through the thickest shackles available.
If you're locking in the same place every day, then stash a HEAVY chain there. Or two. Something like this:
Bicycle Fixation: Security
..And add a u-lock.
I'd get a beater for this sort of job. I would NOT have nice "components" on it, because people will strip these or cut through the frame and carry it away to get them. Buy a 90's hardtail MTB, paint the frame an awful color and giver it with dozens of UGLY stickers (thieves hate removing them), put $10 thumbies on, slosh paint and epoxy on the rims, dremel the brand names off the derailers and brakes, rip and duct tape repair the saddle, then add good locks and skewers - you now have a bike that might deter thieves because you haven't left a single component on it that can be sold effectively. (Except the tyres, I suppose.)
Otherwise, just lock in the best place you can, use those skewers and multiple locks - one chain and one good u-lock (positioned so it can't be levered or bottle jacked without destroying the frame) and trust that you don't get unlucky.