For best security, if you're using a mixed cable/U-lock pair, try to use the U-lock to secure the bike to the pole, rack, or whatever you're locking to. If you use the cable to lock to a rack, and the U-lock to lock the unsecured wheel to the bike frame, a thief could snip the cable, toss the bike in their car, and take it home to defeat the U-lock later.

Funny thing about chains and my bikes -- I've got the 110cm OnGuard Beast chain lock. It's juuust long enough to wrap through both wheels of my road bike and around a typical inverted-U bike rack. The 100cm Kryptonite chains would be too short. I'd like to either "try on" one of the larger 5' Krypto chains (wonder how big they'll be around my body) or just get one of the mini-locks that Kryptonite uses on their chains.