Dry beans, cooked in your rice cooker. Faster and easier than the crockpot, no need to soak. Its easy to freeze portions, and much cheaper than buying canned beans. If you are just going to eat them, I would highly recommend adding the optional stuff, they are pretty blah alone.
Update after some reviews: I make these all the time and they never take over 2 hours, but it may be that my rice cooker cooks at a higher temperature than others. They keep pretty well if you leave them on the 'warm' mode, so maybe you should start them early the first time to see how they do in your rice cooker. You can add onion, butter, meat, etc in with the beans at the beginning, but it will probably be mushy when the beans are done. I have made the mistake of adding tomatoes to start with, and the beans will not cook at all if you do that. :)