For me, that "commuting and errands" category has several sub categories. I'll use almost all of my bikes for commuting, but only some in rain or snow. And if errands involve hauling groceries, I need to use one of two bikes that have rear racks for my grocery panniers. And if hauling involves a whole bunch of stuff, then it's my Specialized Hard Rock that's set up to hook on my trailer.

Another category for me are Brit bikes for club rides (my group is the Veteran Cycle Club--New England chapter). I have a few too many of those.

Neal