A good soldering iron would be numero uno. I use weller solder stations and they are freakin' awesome. They heat up really fast. Usually it takes like 10 seconds and they are ready to use. Plus the heat is adjustable. I have a cheaper one and it just doesn't cut it since I started using the weller. They are expensive but well worth it. Wire strippers are handy and so is a solder sucker. I also keep a pair of hemostats close by. Things that aren't really must haves but are helpful...the aligator clip stands from Radio Shack(they hold stuff for you while you solder), an ohm meter(to test pots and pups), shielding paint is nice but expensive and not always necessary, some cables with aligator clips on the end so you can test stuff without soldering, I'm sure the list could keep going but that'll get you rockin'.