Once I learned how to tie that knot, I was using for all sorts of things outside of hiking.
A Prussik is dead simple and very useful.
Adjustable grip hitch http://www.layhands.com/Knots/Knots_...tableGripHitch
easy to tie, grips better than a taught line, and can be finished with a slip knot. I use it now for my suspension line (no woopies).