My commuting "kit"
Crank Bros Multi tool - various allen wrenches, screwdrivers, chain link remover, nipple wrench.
Tire lever
Patch kit w/ glue
Small adjustable wrench (about 6" long)
Extra AAA batteries for my taillights
Spare bike chain "quick-link"
1 gallon ziplock bag (keeps the seat dry if parked outside)
Clear saftey glasses for riding in the rain/wind. (getting crap in your eyes sucks)
2 small bungee cords (about 8" long)
Full size frame pump
Kryptonite Evolution mini U-lock
If I bring one of my panniers (which I usually do) I also bring the following:
2 medium bungee cords (about 18" long)
1 large bungee cord (about 24" long)
2 Velcro straps (about 24" long, hooks on one side, loops on the other)
6' Kryptonite Cable and Big eff'n padlock
umm...nice turtle....