Cast iron is great, and very very useful.
It's basically the opposite of why you buy a copper pan: the copper pan heats and cools quickly, so if you use a gas burner and need something JUST RIGHT it won't keep sending heat into the food once you shut off the gas. Cast iron on the other hand heats up relatively slowly, but keeps that heat evenly all through the pan.
It's awesome for woks, which are great versatile pans even for camping, skillets, ovens, you name it. One of the best features is that even if you want to bake something, the iron transfers the heat so well to the rest of the pan that you only really need one direction of heat; from the bottom on the stove, or from the sides with charcoal in a pit.
Like a couple people have said, cook non-goopy fatty stuff like steaks and bacon for the first dozen times you cook in the pan. A lot of people like bacon fat to break in their pan. If someone in your family is a hardcore vegetarian, just use corn or canola oil padded all over the pan with a paper towel. You can speed things up by coating the whole pan lightly in oil and throwing it in the oven three times; first at 375 and cool, repat oil, then 425 and cool, repat oil, and then 450 or 475 and cool. It will smoke at the hot temperature, but you're not hurting the pan. Once it's cool, slather it in oil again and put it away.
You can use soap, but make sure you don't use too much or for long; just enough to cut the grease from cooking, and then wash it off. Never use a scrubber if you can help it, or you'll have to reseason. If you have to reaseason, big deal, just fry some bacon a couple times.
Lodge is great, but they aren't enameled. If you want to cook your food and put it in the fridge in the pan, even a seasoned pan will rust and flavor the food; you'll also have to scrape the rust off. Enamel pans let you cook whatever you want without rusting or flavoring the food. For example let's say you cook up a nice tomato sauce and are too lazy to put it in tupperware.
There's a couple brands from france that are just as good as le creuset, but much cheaper, I can't think of their names. Also Lodge makes a couple lines of enamel that's made in Switzerland or something.
After washing, pat the pans down and dry them upside down.