When I worked IT, I carried the following:

Leatherman Supertool.
McFeely Pocket Wrench.
Doc Allen Versatool w/ a selection of bits.
Modular precision screwdriver w/ straight, hex, torx and philips bits.
Mini-mag w/ the fiber adaptor.
at least one more light.
small hemostat.
dental mirror.
thumbdrive with my apps and data on it.
thumbdrive with antiviruses and the like (not putting my drive in a dirty box).
Knoppix CD.
Trauma sheers. (bad cable? no question about it after I cut at least one end off)
Zip ties, electricians tape.