I am a believer in beans.
I make a tuna-style sandwich filling out of mashed garbanzos. (Minced pickles, red onions, celery, Veganaise, mustard.) I think it's yummy.
I like making a kidney bean dip (mashed kidney beans, olive oil, balsamic vinegar, scallions, celery, salt, pepper).
The lentil salad mentioned earlier sounds pretty darned good as well.
I love soup as well. The little crockpot thing sounds pretty neat. You can make a lower-cal "creamy" soup by pureeing part or all of a veggie-based soup. I'm not sure that it would be so effective with a meat soup, though.
Salad is another favorite of mine. I have eaten salads about the size of my head and they still clocked in at under 500 calories. Just use a variety of greens and veggies that are flavorful and water-dense. (I like cucumbers, fennel, bell peppers, and sprouts.) You can add some dried fruit or veg if you like it. You can make a rendition of a creamy dressing by using strained yogurt and herbs, thinned (carefully) with vinegar or citrus juice. I normally use balsamic-vinegar-based dressings. Toss on something proteiny. Beans? Cheese? Meat? Nuts? Cold cooked potatoes will also really stick to your ribs.
Roasting vegetables gives them tons of flavor. I love roasted fennel and shallots. I toss them with a little oil, salt, and pepper, and cook them until they're tender and caramelizing. I then drizzle on a dressing made of orange juice, honey, and cayenne. It's good on cooked grains of some sort. Or on its own. Or both. I also love roasted root vegetables. I make a roasted root vegetable hash that is pretty good the next day (beets, potatoes, sweet potatoes, onions, and carrots tossed in oil, balsamic, soy sauce, salt, pepper, and fresh thyme then roasted until it's cooked the way you like it).
If you like mushrooms, the portobellos make a nice relatively low-cal sandwich filling.