I try to eat a lot of high fiber foods. I definitely notice that they help stave off the hunger pains (be sure to drink your water, though!).
For breakfast:
whole grain cereals are good; sometimes when I'm in the mood for a "treat" cereal (Reese's Peanut Butter Puffs -- breakfast of champions) I'll cut it with some all-bran to boost the fiber in my bowl but still get to eat the sweet stuff.
Kashi Go-Lean now has an "instant" hot cereal. The vanilla flavor is 7 g of fiber per packet and I keep a shaker of cinnamon in my desk and sprinkle some in as well. (note: despite being labeled as "instant" hot cereal, it does require cooking time in the microwave.)
Van's and Kashi make some frozen waffles that are pretty high in fiber. I heat frozen wild blueberries or frozen dark cherries and use them as waffle topping instead of syrup.
For snacks:
Some yogurts now are a nice little source of fiber. Dannon makes a light n' fit with fiber variety. Stonyfield Farms adds inulin (fiber) to its yogurts -- amounts vary so check the labels.
lunch/dinner:
Bean-based soups are a great source of fiber -- lentil, vegetarian chili, split pea soups. Some vegetable soups are decent in the fiber count, too. Many are high in sodium, though. I like the Tabatchnik frozen soups.
Beans on their own are a good source of fiber. Also, so are many vegetarian meat replacements.