There are two services now, one run by the National Bike Registry and one supporting it, that provide you with a serialized "tamper resistant" label that ties a unique ID back to your personal info.

The service that branched off from the National Bike Registry is BoomerangIt.  The other is provided by LoJack and is called ReuniteIT.  Both offer to let you trade cash ($10-25 depending on package) in order to provide you with labels and a nationally accessible database so that law enforcement and good samaritans can notify you when they've found your stolen bike, trike, or quad.

Both services claim to provide labels that are sufficiently difficult to remove, though neither addresses the scenario of somebody simply covering the label or painting over it.  Both also offer transfer capability should you sell the bike to a new owner.

Is this an effective method of recovery?  I've not tried either service and also haven't had a bike stolen since 1998, so I can't comment much on that.  But after investing $1K+ for a recumbent, it seems like $10 for a ten year registration isn't going to hurt much if it increases the likelihood of a returned cycle even just a little bit.

Aside from these national registrations, it's a good idea to record the serial numbers of your frames (if stamped), take multiple photos of your bikes, and record any customizations or equipment changes you might have made that make it unique.  It is also recommended that you engrave unique numbers into your frame in order to further identify the bike as yours.

If your bike has been stolen, you can always try registering with Stolen Bicycle Registry. It is a free service.