I bike to the station and then take the train in - it's a loooong train ride, so I like to sleep. This means no breakfast or caffeine when I get up - I wait until work, otherwise, I'll have too much energy to nap on the train. I also don't like riding right after I eat.

Right now, I'm doing the "low carb" thing, so I was getting scrambled eggs + bacon at the caf every morning. This is getting pricey, so I'm now packing in breakfast, which I'll make the night before, refrigerate, and pack in a re-usable plastic container, which then goes into a soft-sided insulated lunch bag. My lunchbag zippers shut and buckles to the outside of my commuter pannier - it's really small, but, will hold both breakfast and lunch plus ice pack, and has a little pocket for utensils.

Here's on the menu for next week:

a) A pair of hardboiled eggs, and a few slices of canned corned beef browned in the skillet (like hash, only w/o the potatoes.) I nuke the corned beef and eat the eggs cold with a little black pepper.
b1) Breakfast burrito with toasted low-carb tortilla, scrambled eggs, shredded fontina cheese, sauteed bell pepper and linguicia (Portuguese sausage popular in Rhode Island. Spicy italian or BBQ sausage will work. I hate breakfast sausage.) Do up the sausage, peppers and eggs in a scramble, wrap in a tortilla. Nuke at work.
b2) Breakfast burrito with thin-sliced or chopped steak (or steak-ums if you're feeling lazy), sauteed mushrooms and onions, shredded cheddar and scrambled eggs. Nuke at work or the steak will stick in your teeth.
c) Tunafish salad in a low-carb pita pocket - tuna, diced celery and mayo, with a few greens, a slice of sharp cheddar, and a thin slice of onion. (I also pack a toothbrush.) Eat cold.
d) Cobb salad - sliced hardboiled eggs, fresh, crumbled bacon and a few slices of avocado on greens with bleu cheese dressing or bleu cheese crumbles. Eat cold.

Non low-carb options for cheat days (or when I have a cold - don't diet sick!):

d) Salmon and brown rice kedgeree - works either hot or cold. I don't like trout, and salmon is available in the can if I'm lazy and don't want to cook up a fillet or steak. Brown rice is one of those things I used to think was health-food store junk, but it's beyond tasty when cooked right.
e) Oatmeal - get some nice steel-cut oats, and a mini-crockpot. Cook all night at the lowest setting with a handful of slivered almonds, crushed walnuts, craisins, raisins and dried cherries, and a few sprinkles of nutmeg. Will be sweet, tangy, nutty, and keep you full until dinner. Pack it in a little thermos or nuke at work.