Soups are an easy and healthful crock pot dinner.
Split pea soup is a favorite in our house. I prefer using a ham hock, but you could probably do a veggie version or use turkey bacon. An immersion blender makes this much easier.
We haven't tried our black bean soup in the crock pot yet, but can't think of a reason for it not to work. 2 cans black beans, rinsed and drained. Smash one can's worth with a potato masher. Add one bag frozen pepper strips, 1 jar salsa, 1 pound cooked meat or sausage (or the veggie crumbles), 1 can broth.
Going to try this one later this week:
http://crockpot365.blogspot.com/2008/08/restaurant-quality-crockpot-tomato-soup.html
Since we don't have 3 lbs of tomatoes from our patio, I'll be using 2 large cans of whole, peeled tomatoes.
I think we've done butternut squash soup and a carrot ginger soup, too.
Beyond soups: Chicken thighs with barbeque sauce. 8 hours on low, shred and serve on buns. Works with pork butt, too.