I'm assuming theses are going in a portable kit and not a stationary car or office kit.

Leatherman CS4 Juice, or Swiss Army Craftsman for single tools.

For a tool kit:
1) Needle nose Vice Grips
2) Stubby adjustable wrench
3) Good quality compact sharp scissors.
4) Good quality compact multi bit driver and your selection of bits. Include the larger finger ratchets as well as stubby drivers in this catagory:
5) Voltage detector pen
6) Small prybar (i.e. catspaw)

Other stuff carried in addition to the above:
3X5 or 4X6 notepad
Reliable ballpoint pens
Keychain tape measure
Spare power source for your cell (i.e. Energizer Energi to go)