Considering the choices you are dealing with, you can't really make a bad one. All the Glocks are great carry pieces, especially the G26/27/33 the G19/23/31, and depending on build/need, the G29/30. There is also the G36. All are great choices for CCW.
So I'm gonna say this again because it is so important. Focus on getting a GREAT holster and belt. You may have to wait awhile for a good one. While some folks like Galco, they are mass produced and not what I consider great. Look at Milt Sparks, Mitch Rosen, and Lou Alessi to start with for some great holsters. The Milt Sparks VMII, VersaMax2, has interchangeable belt loops for different belt thickness, and you can get kydex belt clips so you can tuck in a dress shirt over the holster. It fits tight against the body, and the belt loops are on either side of the IWB holster as opposed to being right on top of the holster. This makes the width profile of the holster much slimmer, spreads out the weight of the firearm, and makes it more comfortable in general. Great, great holster.
For the belt, you need a stiff gun belt, stiff as in that it won't fold. I use a double thick 1.5" belt (when two softer belts are sewn together, they yeild a soft comfortable belt that won't bend or fold). Mine is made by a local leatherworker, but Milt Sparks makes some great belts. Lifelong type stuff, everything they do is handmade, I can't say enough good about them. Definitely worth the wait, if you plan on going with these guys though, I'd order the holster before getting the pistol.
Also, make sure the loops on the holster fit the belt you get. If you get a 1.5" double thick belt from maker A, it may not fit maker B's 1.5" loops. It may be better to get the belt and holster from the same maker.
This holster/belt issue never comes up enough, but it is equally important, maybe more so, than the selection of the firearm itself. It dictates how comfortable the carry will be, how secure the draw and reholster is, and how well both the holster and pistol as a whole conceal against your body. Each component is equally important too --my nice VMII's don't conceal well at all when worn with a cheap department store belt, and my kydex holster with too large loops sort of hangs off my nice gun belt.