a few things to respond to:
1. avocados number asked if you need a masters to teach and whether they would ask the nobel prize winner in physics to get a masters in teaching. the answer to both questions is yes. part of this has to do with NCLB requiring that all teacher be "highly qualified" in their subject area which means attaining a masters within your first x yrs of teaching. a little ridiculous since no study has ever proven a causal link between student outcomes and teaching certification, but it is what it is.
2. i actually was a teacher for two years and now am in law school. i had a somewhat unusual teaching experience in that i worked probably 65-70 hours a week and spent the rest of my free time thinking about teaching. it was and is the hardest thing i have ever done, hands down, and i expect working at a law firm to be a joke in comparison because no one will ever throw a piece of furniture at me while i am an associate. can not say the same for when i was in the classroom. that being said, i expect to feel empty and useless as a lawyer and won't stay in it very long. my intention is to work to pay off my debt and then get back into education working for a district at an administrative level. i initially thought law school was going to be helpful to my career goals, then decided otherwise but couldn't get a job last year. when it was down to the wire, it seemed like a foolish thing to do to say no to a t-14 school and remain jobless in the hopes that something i liked would come along. in retrospect, i wish i had the balls to do just that. now i'm swimming in debt and nothing but a big law salary will help me get out in any reasonable amount of time. i guess fortunately or unfortunately depending on your perspective, i'm in a good position to get one of those jobs, but as earlier posters pointed out, most people don't get big law jobs. at my school, though, it is probably like 60% of our graduating class.
anyway, as far as my experiences relate to your dilemma- don't go into teaching if you aren't passionate about helping kids and making a difference. we have too many apathetic teachers as it is who are just there for the 10 month yr and short hours. that being said, you are going to graduate from law school with a ton of debt and since you seem resigned against the firm route, i don't know how you are planning to repay it. i guess you could just hope to rock the lsat and that your gpa is good and get a bunch of scholarship money, but admissions are going to be rough next year because lots of people apply to grad school when the economy is down. one last piece of advice- don't wait until march to send in your apps. have everything done and then just send them pending your lsat score from the december test. most law school admissions are rolling and you put yourself at a disadvantage waiting until after jan. 1. good luck. you seem to have decided on law school, but just keep in mind what i have said given what your aspirations are for what your life will be like.
one last thing- you can definitely run 1L year. people who say school has to be your whole life are full of it or never had to manage their time previously. if you were a collegiate athlete at a school that was at least semi-demanding academically, you'll be fine. i was so bored in 1L year that i started working and volunteering. people thought i was insane but i knew what i could handle and it worked out totally fine.