Thanks very, very much. I'm embarrassed to admit I probably spend 3-5 hours a day on a command line, and have just gotten used to set -o vi when I need to bounce around long lines a lot. esc+f/esc+b were always awkward. It should have occurred to me to just map the keys on Terminal.app!

In the interesting news department - Lion already has option left cursor/right cursor already mapped to move a word forward and back - not sure if it was there in snow leopard.