Years ago, I decided on my hunter that I like having the spacebar to move back a step or two, so I moved my jump over to the down arrow.

I find this still handy in dual-boxing. Spacebar to move back a step or two, to bring a mob in melee range of my second toon, and the jump is still set to down arrow. On my second toon, spacebar is set to nothing...

Try it, you might like it!