Hammer and knife
The two tools I use most at work and they both belonged to my grandfather. The hammer's a solid old lump with a leather hand grip; none of this lightweight, hollow crap I keep seeing. The knife's something that he made himself to fit Stanley blades, because he though Stanley knives were shoddy and ill-made.

They never leave my side. I even take them home with me to keep them safe. The rest of my tools can be replaced.
(Unit, Sat 6 Nov 2010, 4:14, Reply)