The first five years I was a CBP Officer we carried the Glock 17. It wasn't a bad duty gun; with three magazines and one in the chamber it was like carry a box +1 of 9mm ammo! We carried them with Speer Gold Dot LE 124 gr. JHP which is more then adequate for a 9mm round.
Although not a Glockaholic or fan boy I do have two Glocks. The first one I bought was a Glock 29; described a few years ago (when I bought it around 2006) and still is listed as a sub-compact on Glock's website. Hmmm a double stack, 10mm, 3.77" barrel - I can live with that sub-compact. What I like about the Model 29 is its ability to change calibers by merely switching barrels. It comes with a 10mm barrel; I bought Lone Wolf barrels in .40 S&W, .357 Siq, and 9x25 Dillon which is essentially a 10mm case necked down to 9mm. Image, if you will, a 124gr 9mm JHP at 1,600 fps! Is it any doubt which extended and ported barrel is the 9x25 Dillon? Like shooting my Coonan .357 Magnum 1911 shooting the G29 loaded with 9x25 draws a crowd!