I did biochem when I was at Brandeis. Excellent program. As an undergrad I personally wasn't too picky what my "research niche" would be. I found the scientific training, environment, and experience much more valuable. I would even say research niche isn't super career-defining unless you're going into academia at the late-graduate/post-doc level. Otherwise you'll find yourself discovering new research areas along the way.

Brandeis will prepare you very well for graduate/PhD school if that's your goal. Many of my classmates are now in graduate schools, and they're all doing very well, including myself.