Automatic Wire Stripper/Crimper
If you don't have one of these in your kit, and are going to tackle wiring, you'll want this guy as your side kick. This has a wire cutter, crimp positions for insulated and uninsulated terminals, and (of course) automatically strips wire from 10-26 Gauge. It pretty much does it all, except wire your bike for you.
Looking for a less expensive option? Try the Automatic Wire Stripper. The crimp positions aren't as great as the one pictured here, but it will work if you already have a set of crimpers in your toolbox.