9mm is an excellent choice
The 9mm is an excellent choice. It will do a fine job of defense, especially with the hollow point. The 9mm is my personal favorite and the round I use for home defense, I trust my family to my 92FS (btw - the SR9 is a pretty nice gun, it's the next on my list to pick up I think - good choice IMO). Overall I think the 40 s&w is the best compromise of all around punch, more weight while maintaining higher velocities. I still like the 9mm best for several reasons. 1) It still has plenty of stopping power, it has less recoil and is therefor more manageable, you're more likely to hit what you shoot at, especially on the 2nd and 3rd shot. If you miss, it doesn't matter what caliber you shot, a .22 that hits is more effective than a .45 that misses. 2) It's cheaper, so you will shoot it more which leads to again, you're more likely to hit what you shoot at. 3) It's more available (at least in my area). 4) More rounds in the clip ... more is always better in my opinion, the SR9 holds an awesome 17rds. 5) There is a larger selection of guns for the 9mm including a few key choices that don't exist in the 40 and 45. The Beretta 92 and the SR9 are 2 examples (and no, the 96 is not a fair substitute for the 92, Guns designed for 9mm and 40 are ok but 9mm's reworked to handle the 40 are off my list, the Ninety-Two in a .40 might be ok, the 96 ... it's a nice collector but I'd rather carry the 92). 6) Most 9mm's hold twice as many rounds as the larger calibers do, I'll argue that 2 9mm hits have more stopping power than 1 .40 or .45 hit does which means the 9mm as a whole has greater stopping capacity in my opinion.