I like using a crock pot about once a week in the winter. So I've developed a basic approach to cooking in one which is adaptable to various ingredients. Usually it works out pretty well.
The important thing is that unless you have six kids, you should look for a smaller crock pot. Mine's a 2.5 quart model, about half the size of Mom's old "three turkeys and a ham" pot. The smaller size works out quite nicely with standard food packaging.
So here goes, tonight's dinner (plus a few future lunches):
1.5 pounds of uncooked mild Italian sausage, cut into short pieces
1 big can (the double-size can) of diced tomatoes
1 tiny can of "tomato sauce"
(one of those two cans had "Italian herbs" already mixed in from the factory)
a couple cloves of garlic
usually there'd be some onion, if I had remember to buy one
didn't need salt, plenty in the sausage and tomato sauce
a bit of fresh ground pepper
about 1/3 cup of uncooked rice.
Throw all this into the crockpot before going to work, top up with water, and leave on "low" until you get home.
So here's the theory section. You might have noticed that I didn't say to brown or precook the sausage. Instead, it cooks in the pot with everything else. The uncooked rice is important, because it soaks up excess grease. I don't even bother browning ground beef, I just buy the least fat version (about 95% meat, 5% fat). Yes, it is considered healthy to throw away grease from cooking. But that grease is energy, it's part of why we bother eating. If you want lighter food, you can compensate by just putting the soup/stew/chili on regular rice or noodles to balance it out.
I haven't tried a vegetarian version of this cooking approach, but I'm sure it's possible. Probably would cook much faster as well. Something like a fake meat product (the "Gimmee Lean" sausage is pretty good) with added olive oil would probably work out quite well.