Handgun choice is right up there with the most personal of choices, way more so than Land Cruiser v. Land Rover and Ford v. Chevy. What I might pick might be totally different from somebody else and both may be the right answer.
Start with a quality firearm from a reputable company (what's reputable? find one of the guns being carried by professionals is a good start). Rent as many models as you can and test fire them at a range. Go with the one that fits your hand(s) best and then your specific planned carry/use regimen. Buy it + a boat load of ammo + quality holster/belt and get excellent instruction and train enough so that the motor skills are downloaded to your mid-brain so they can be performed under stress.
It may be you wind up with a Glock, 1911, a .32 Seecamp or a .454 Casul.
Solid advice right there. I have carried the following guns professionally (Glock 17, 19, 21, 22, 23, SW 5906, SW 4006, Beretta 92, Sig 226 and a Colt 1911) all have their pro's and cons. I feel you need to get the highest quality firearm you can purchase along with a "QUALITY" holster and other support gear. The most important thing is going out and getting behind the gun. Seek out professional training from a reputable instructor, put the time in necessary to be a professional with it. I currently CCW a G-19 w/ IWB or a SW Shield 9mm IWB. For my daily working gun I use a Gen 4 G-17.