You know you need to lock your bike. But how? It is true that there is a right way and a wrong way.
Sheldon Brown's advice on locking your bike should be required reading for all bike commuters.
I have a keycode-access shed at work and a locked shed at home, so I just need to carry an ordinary cable lock for quick stops. I have a boring black lock but I can't help but think that there must be something better!
Here is one option: For the lightweight cable lock that one carries all the time, these French snake locks are fun (if you can stand snakes!) The snake is available in many colors to complement your bike.