I recommend a good tone generator and probe kit. Prpgressive electronics/Greenlee makes a good one. The model 200fp is a good probe. I don't know the model number on the generator but I think they sell them as a kit on their website. It runs around $150. That is my invluable tool. No measuring, no blueprints, no guesswork. Just tone out the wire behind a wall and find your studs. It's that easy. I recommend a Dewalt 14.4v XRP drill. It is more versatile than any of the others and has just as much power as the 18 volt models. It is by far the best drill in 99% of jobs. Labor saving devices is also a great place to find tools(fish rods/tapes, wet noodles, drill bits for any situation, lots of handy tools). An SPL meter is also a good idea. you can get one at radioshack for $50-$60. There are so many tools you may needdepending on the type of jobs your company does.