Okay folks - first off, you will never see me advocating avoiding anything on this blog because it's scary, going to cause cancer/world war III, or is simply "evil," however, I will advise you avoid things because they use too much energy and are questionable in their safety or the purpose they're billed for. Microwaves easily fall into the questionable category. They are, surprisingly enough, not much more convenient than a standard small pot or pan, and what you loose in taste and texture is so much, that I would suggest that you start phasing yours out. Even I, who deplore doing dishes, prefer to wash a small pot to losing all of the good, hard work I've put into my meal by reheating it in the microwave. Toaster oven or stove top is ALWAYS tastier. Also, if you experience power outages in you kitchen, chances are your energy-guzzling microwave is to blame. At the very most, it's worth considering your microwave a fancy and expensive bread box, or a mouse-proof cabinet.
Here's the how-to on reheating without a microwave:
Rice, other grains, and cooked beans are reheated by adding a bit of water to the bottom and simmering, covered, over a low heat. If you're impatient, turn up the heat and stir the grain every minute or so to make sure it doesn't burn.
Soups are reheated the same way they are cooked. If they're very thick, add some water or stir frequently so the bottom doesn't burn.
Casseroles and pan-fried meals For the sake of expediency and deliciousness, I'd reheat these by frying on a hot pan. Refried meals (like beans) are delicious because you've added oil (or, even better, butter), browned the bottom, and mushed things together, which makes everything taste better. if you don't like things mushed together, add a little liquid to the bottom, cover, and heat over a low flame. If you have a lot of time to kill, throw it into your oven or toaster oven, covered, on 350 degrees and wait.
Anything meant to be cooked in the microwave such as frozen burritos and tv dinners can be cooked (covered) in a pan or in the toaster oven. In the case of TV dinners, transfer to meal to an oven-safe baking dish before melting plastic in the toaster oven. This is the only case in which it will take more time to cook, but burritos are much less soggy when toasted or fried, and tv dinners will thaw very quickly in the frying pan but will still be disappointing. In the case of Ramen noodles and such soups, cover with boiling water until cooked or simmer for a minute.
And please, immediately throw away any recipe books for "microwave cooking." This is not cooking. It is, in fact, a farce. Anyone who thinks their 12-year-old child can't cook a meal without the help of the microwave would do well to wonder how 9-year-olds helped their mothers in the kitchen 100 (or even 70) years ago.