Beef stroganoff. 1 1/2 lbs beef cubes, an onion or two, mushrooms, and a cup of strong buillion in the crock pot. Cook on high for a couple of hours. Add a pint of sour cream, thicken with flour. Serve over wide noodles (you can do noodles in a microwave).
Swiss steak. Buy it cut or buy bottom round and cut it into steaks. Dredge in flour, salt and pepper mix and put in crock pot. Add a chopped onion. Cook for an hour on high. Add a can of diced or chopped tomatoes (just enough to cover the steaks), and let simmer for 3 or 4 hours. Add a buillion cube or three for taste, thicken with flour, serve over rice (minute rice works in a microwave).
I've done Mac and Cheese. The chicken + bbq sauce dealie that Wayne mentioned (with the same 'make it again!' response.. the trick is to cook long and slow so the chicken falls apart, and you serve 'pulled chicken' on burger buns). Ham & String beans (cubed ham, cubed potatoes, string beans, water... cook until potatoes are done, sorta like a soup/stew). Chicken and dumplings (cheat, use Bisquik).
The biggest downside is the limited heating power of the crock pot... can't really boil anything. Just think of what you'd make in a dutch oven, and tweak it for a crock pot instead.
I just made a fantastic 16 bean soup. The recipe is on the bag of beans, but I kicked it up a bit by adding a can of fire roasted diced tomatoes and keilbasa. throw it all in the crockpot. It's similar to a good bean chili. I added my own spices too: worstershire, br sugar, srirachi hot sauce, cayenne, paprika, etc.
grab a bag in any store - I was surprised at how great it came out and hearty it was.
You don't have to prepare food on the stove first before using a crockpot but I find it makes a big difference for meat dishes. I won't cook meats in the crockpot unless I brown them first. They taste mushy otherwise. That said, there are a lot of recipes that don't call for browning.
I like lasagne in a crockpot, and if you use canned sauce, you can just assemble and cook. I use no boil noodles (it's perfect with the moist heat of the crockpot) soaked in hot water first, then squeeze the water out w/ your fingers. Extra sauce--more than you'd think. Both bechamel or ricotta work fine. Layer like you would a baked lasagne.
Wihout cooking first? TONS of stuff. Not everything needs to be browned first, although browning will improve the flavor, Let's see....
Beef Short Ribs
Osso Bucco and other braised shank recipes
Pulled Pork BBQ
Ropa Vieja and other "shredded beef" dishes
Cooked whole chicken for making other things like BBQ chicken, chicken salad, chicken casseroles, etc.
Beef, lamb, or pork Stews of many, many kinds and cultures
Soups of a thousand kinds