SingingSabre 

I use a U-lock through my frame and front wheel, then run a cable, a la Sheldon Brown, from the rear wheel to the U-lock.

I would do it reverse, as per Brown's advice, but the FreeRad just isn't removable unless you have some time or really need to take it off.

At least with the U-lock and cable, you're still set.

Lately (since Jan) I've even skipped out on the cable. I figure if they really want my rear wheel and are willing to dig under the FreeRad and rassle with a heavy bike locked to a post, they'll be willing to snip any size cable.