https://www.kryptonitelock.com/produ...=1002&pid=1168
here's the new hotness. there are also a few slightly more reasonable ny lock/chain combos, but overall, if you want your bike safe, these are pretty much the way to go.
I've found that with the 3'3" chain I have, normally I just lock a wheel and the frame, but if I'm leaving it anywhere for an extended period of time, I can thread the chain through both wheels and the rear triangle, and around whatever I'm locking to (street sign/light pole). It's great if I ever have to leave my bike outside at night for any extended period of time.
the new one that i linked to might have links that are a little too fat to easily slip through spokes, but it's still probably possible, and if not, one of the other, smaller chains will definitely work for that purpose too.
addition: banzai, true, if they want the whole bike, they'll get it, but at the same time, being able to lock both wheels and the frame eliminates the most expensive single pieces from wandering away from your bike. If there's anything worse than coming to find your whole bike stolen, it's coming to find that a wheel has gone missing because you didn't lock it.
OP: in general, a solid ulock will be fine. However, if you're like me and dont like leaving parts for the taking with a mere 15mm, then either get a chain and lock wheels and frame, or get an auxiliary lock for the other wheel if you plan on locking up for an extended time or overnight.