Yes, the idea of biking in Boston scares me. About 90% of the people I know who ride bikes in Boston have gotten in at least one accident. The streets are very crowded.

"In general I found having a car was a pretty key part of living in Boston."

This is true for you, but not my experience. I moved to Boston in 2008 and got rid of my car. I've been living car-free for four years now. I thought I'd need zip cars or cabs every once in a while but I don't use either. I mostly walk everywhere (I live in Cambridge) and occasionally take the T.

The real story is not how bikable Boston is, but how walkable it is.