It may be overkill for most, but I brushed up on the research focus for most of the non-practice faculty. My background is in biomedical research, so I was pretty certain that I'd get a a Ph.D interviewer, which was correct. Being able to discuss his work from an informed perspective (albeit novice in his area of interest) was a big plus. We ended up going well over the interview time, and my "interest" in his work prompted his interest in my work, so it was a good strategy in the end as it allowed me to focus on my area of expertise. It ended up being a faculty member with an area of interest completely unrelated to my background, so I would have been clueless if not for reading a few of his recent publications. The caveat is that I only applied to one school and thus was able to focus on the ~20 researchers most directly affiliated with the program. If I was interviewing at 5 schools over a months duration, like many here, it would have been very difficult to assimilate the background to the extent that could be applied during an interview.
