The benchmarks would probably be somewhat misleading in a lot of cases here. I'm fairly certain that most compilers will replace a /2 with >>1 for example, so that isn't really going to end up being reflected when you compile it.
EDIT: http://blogs.msdn.com/b/shawnhar/archive/2007/03/19/a-story-... gives other reasons why multiplications can be faster than bit shifts.