Here’s a nice little list of some essential tools, with my suggestions.
A good multi meter is essential. This is my choice.
FLUKE 15B+ F15B+ Auto Range Digital Probe Multimeter
Digital calipers are nice – non conductive plastic ones are a smart move.
Starrett 799A-6/150 Digital Caliper
For crimping large lugs –
Forney 57637 Lug Crimping Tool
If brute force doesn’t work, you’re not using enough:
Central Hydraulics 12 Ton Shop Press
Making connections…
…and sealing them up.
Portable hacksaw power
’nuff said.
Wire sizes and funny numbers…
The Electric Chronicles: Power in Flux 