Around here it is Glock or S&W mostly. A few departments who are anti-Glock go to something else like <barf> Beretta or more recently Sig. Raleigh PD used a S&W 3rd gen POS for YEARS until S&W finally told them they were not going to support the platform anymore, so buy new ones or start sharing parts. The Troopers use Sig or Beretta. They seem to change a lot, currently on a .357 Sig kick, and a one time used Cougars and then went to Sig 229's I think. I have never seen an NC department with anything HK. Glock 22/23 gets a lot of love.
S&W recently bought all of Guilford County's Sheriff's Department 15 year old Glock 21's for S&W M&P .45's. Now they can't seem to get their qual rate above 60%. On a side note, I hear the higher ups had HK USP Compact .45's as their "Duty Guns" but mostly sat in desk drawers. With the jobs come the perks I guess.