I have a (plastic) water bottle that is dedicated to carrying cold espresso + skim milk made the night before. I nuke it on arrival (in a glass mug). At my desk I keep instant oatmeal packets plus cinnamon, craisins/raisins to stir in. You can also make your own "packets" using quick-cook oatmeal and a sammich baggie. I keep a corelle bowl and real flatware at work - no plastic stuff in the microwave. They clean easily and aren't annoying like plastic spoons that break or have sharp edges.

For emergency use I also have a box of powdered milk, coffee, flavoring syrup and coffeemaker. At one time I had a cheap espresso maker at my desk. The powdered milk -- sometimes you gotta do what you gotta do. The syrup helped kill the off taste.

I have a few pieces of dried apricot and some swigs of diet coke to get me out the door at home.

Peanut butter can be kept unrefridgerated at your desk; I either take enough bread for the week on Mondays or just 3 slices each day. Frozen bread transports pretty decently. That's lunch food for me along with fruit. I am not a fulltime commuter so I stock the desk pantry on non-bike days.