Probably the 45. Before I selected my EDC I shot 9. 40 and 45. The 45 "felt" the best. By "felt", I mean it was the closest to a natural part of me. I then selected the brand and model. I shot the XD, Glock and M&P before making my choice,
I personally would pick the .45 over the .40. Like Howard said, it "felt" the best to me. To me the .45 has more recoil straight back were the .40 are a little more "snappy" recoiling more up and back. I personally felt like I could control the .45 with faster more accurate follow up shots. The mag capacity should not be a big factor cause you'll probably only get one extra round out of the .40.
So the best suggestion I can make is go to your local range and see if you can rent the model Glock you want in .40 and .45. Shoot both. Which ever one is more comfortable and you shot the best would be the one I bought. Then just practice practice practice!
Personally, the 45. Knockdown stopping power versus the extra round or rounds. The 45 can end it faster. The 45 ammo seems to be cheaper than the 40 as well. BTW I have a Glock in 40 and an M&P in 45. Like both, carry the M&P on the road.h34r:
My suggestion would be to try both and see which you like best. The .45 is more of a man stopper, but that won't do you any good if you can't hit what you're trying to shoot at.
I would go with the 45 because I already have guns that shoot that caliber and have ammo in that caliber and I reload that caliber. I don't own anything that shoots 40 and don't want one. It would just be another caliber I have to stock up on and I like the calibers that I have--9mm,45ACP,38 and 357
I have a G27 and a G33. I still rather have a G36 for CC. Even though I don't care for Glocks I'm probably going to get a G36 for my collection.:to_pick_ones_nose: