Beans! Hardly a day goes by that I don't eat them in some form. They are really filling and satisfying.
While high in protein, beans are still starch staples along with other legumes: lentils and peas. Soybeans and peanuts are also legumes, but much higher in fat; I do eat tofu and peanut butter on a regular basis, however, since I'm at a healthy weight and exercise regularly. I also use soybeans to make my own soymilk.
I buy beans in bulk, soak them overnight, and cook them on the stovetop. I use six cups of water per pound of beans for both soaking (rinsing afterward) and cooking. After bringing to a boil and reducing to a simmer, most beans will cook in an hour or so. (Lentils don't need to be pre-soaked.) One pound of dried beans will make about six cups cooked.
I cook one-two pounds of beans at a time and freeze extra in two-cup (approximately one can's worth) portions in Ziploc (or equivalent) freezer bags, flattening them for quicker defrosting. I used to wash and reuse these bags, but boyziggy was concerned about food safety as the plastic is porous. So for now I'm tossing the bags, but realizing that this negates the environmental benefit of not buying beans in cans, I may be freezing them in BPA-free containers (which I'm already using for other food storage) in the future. These will take longer to defrost and therefore require more advanced planning, but that's not necessarily a bad thing.
Recipes abound for beans. The rice and beans recipe from my VeganMofo entry on rice is a good basic one. Curried chickpeas and kale from FatFreeVegan is a bit more sophisticated, but still relatively quick (and a tasty way to get your greens in). I always like to have cooked chickpeas and/or kidney beans on hand for tossing into salads, and pinto and black beans can make quick wraps, burritos, or additions to tofu scrambles.
I learned from Everyday Happy Herbivore that beans can be used to make lowfat vegan desserts! Try the black bean brownies and butter bean cookies. These got rave reviews even from omnivores!