Double box end wrench 12mm and 14mm is my most used tool.
Dewalt 18v cordless 3/8 impact gun - it takes most things off.
Dewalt 18v 1/2 inch cordless drill - I use it for everything including lifting and lowering my car and truck jacks.
Air compressor, it powers most of my other tools.
3/8 drive Metric socket set - specifically 8, 10, 12, 14, 17 and 19mm get used alot.
3/8 drive metric allen keys
I have just added some ratcheting box end wrenches to my collection, they are really fantastic. I was beating on one with a trailer hitch trying to break something free (8 somethings actually) and expecting the mechanism to be damaged, still works perfectly. Nothing like having the right tool for the job.