In my county we have about 5 different small municipalities. They all carry Glock 23s. The County Sheriff Deputies all carry Sig 226s. The Ohio State Patrol also switched to Sigs. In my office, we can choose whatever we want to carry. 2 guys carry Springfield XD40s and I carry my Glock 23 most of the time (sometimes my Colt 1911).
My local SO carries G21SF. I was told by a Deputy that whoever is in charge of there armory is a diehard Glock fan. S&W approached them with free handguns offered to switch and he turned them down. The officer I was talking to also had a G30 strapped to his ankle.