So, I figured there was a lot of valuable insight in a variety of really long threads, but that a lot of these threads are filled with our venting and worrying, and so wouldn't be particularly helpful or entertaining to pick through. So I decided to start this thread so that people could post big picture lessons or pieces of advice they want to pass on to future applicants, and they are in one spot for (hopefully) easy reference.
So, my advice (beyond the standard apply to a wide variety of programs, etc) is on to decide between those last two schools (school A and school B) and you think you love both of them:
When I was in this situation, my advisor asked me two questions that were VERY helpful in letting me clear up my own opinion:
1. Why would you go to school A over school B? Why would you go to school B over school A?
Why it was helpful: by focusing on the differences, rather than the things I loved about both schools, I was able to better see a preference for one school than the other. Also, if you write this list down, you can then rank how important each of the reasons is to you, because it might be that all of the advantages school A has are not nearly as important to you as school B. Don't get caught up in what you "should" feel as it is ultimately your decision about the next 5-6 years of your life.
2. Say you are going to school A. What is your initial gut feeling? Repeat for school B.
Why it was helpful: My gut reaction when I said I was going to A was disappointment I wasn't going to B. I would have been really excited to go to A, but I realized I would be more excited to go to B.
Also, if you find yourself in this situation, remember that while it is stressful, there isn't really a "bad" choice as you love both schools. Either way, it will work out.