Question: I realize that it is important to take on a vigorous course load my senior year. Does it matter exactly what it is? I really can't stand taking Math. I have taken honors math all through high school. Would it be really damaging to drop math and take something like another science course instead? I am not planning on attending any Ivy League schools, basically just a step or two below them.
For the level of colleges you're shooting for, it appears to me that you should have no problem moving away from math and into a science for your senior schedule. As long as you have met the minimum entrance requirements of your candidate colleges (usually posted on their Web site's admissions page), you should be looking quite good, assuming that you can meet their other admission criteria.
The important issue, as always with high school course schedules, is to take solid, challenging courses. It's fine to take constructive electives that parallel your passions, but don't take electives just to make things easy on yourself. It looks like you're making a sensible decision. Follow through with your counselor to make sure that everything is on track for satisfying your graduation requirements.