Anti-theft systems?

[Catbird_imp]

What are some recommended disc locks? (And what size?)

That depends a lot on how much you want to spend and whether you want it to have a self-contained alarm.

I have 3 motorcycles and a very nice Vespa scooter parked in my locked garage. I keep simple "U" locks on all of their front discs and I keep them all covered with inexpensive Walmart motorcycle covers.

I don't really have a vehicle theft problem in my area (that I'm aware of), but these small security measures make me feel better.

The below lock only cost $20 on ebay...