Boolean Functions Where Sensitivity Equals Block Sensitivity
Recently, I proved that s(f) = bs(f) for unate functions and read-once functions over the Boolean operators AND, OR and EXOR, and my paper including the results was accepted to TCS 2014.
(http://dx.doi.org/10.1007/978-3-662-44602-7_9)

You may be attacking this problem. If so, I feel sorry, but I started to attack the problem independently before the question was posted. A preliminary version of my paper was presented at a Japanese domestic meeting in Dec/2013 and the submission deadline was Oct/2013.
(http://www.ieice.org/ken/paper/20131220DBID/eng/)