As someone who spent more than two decades as a classroom teacher before getting a university post in distance education, I sypathize with you, Desperate Dan. If I were starting over again I don't think I would opt for school teaching, no matter how much I like the actual teaching part. I taught in a variety of teaching situations, including fancy prep schools, small rural schools on the pairies, schools in the Canadian Arctic and big city high schools. I pretty much did my own thing, and always got shit from the administration, which I heartily despised. I often wanted to get out but since I started about the age you're thinking of quitting, I was reluctant to drop to the bottom of the ladder and start anew. One thing I have learnt is that schools come in all shapes and sizes. Often, the school from hell exists two blocks removed from a school with happy teachers and nice kids. So much depends on the staff. the administration and the parents. If you're judging all teaching based on one or two situations you've experienced, it might be worthwile to shop around. In Canada (that's the only jurisdiction I can speak about), many schools focus on special programs like French Immersion, the International Baccalaureate or Advanced Placement programs. These programs tend to attracted motivated students, enthusiastic parents, somewhat more enlightened administrators (no guarantee, though) and offer teachers a much nicer environment in which to work. There are other alternative educational jobs, as earlier posters have mentioned, but more often than not, the pay is poor (private, church schools), the working conditions precarious (adult education) or the benefits non-existent.
Business - the corporate kind - often isn't the answer, either (I've tried that, too). I've the impression, Dan, that you are the type of person who would do well in a self-employed situation. I would make a thorough assessment of your skills and experience, balance this with what you really want in life - is money vital or are you prepared to take less salary for more satisfaction? And try to find some area in which you can start a home-based business. Self-employment has its own downside, but I liken it to a manure heap: it's better to be on top shoveling the stuff on other's heads than at the bottom getting it dropped on your own.