I'm relatively new to CCW, and have only ever used a couple different guns for carry.
My Kel-Tec P3AT is always found in my strong side front pocket. The gun was bought when I turned 21 for that exact purpose. With the exception of a box of Magtech FMJ early on it has performed flawlessly. I fully trust it mechanically and have found that I shoot just as good, if not better, with it as my main carry.
My main carry has been an M&P40c IWB at about 3:30-4.It was bought as a workhorse; something I wouldn't worry about the appearance of, just the function. It has never had so much as a hiccup even with the cheapest ammo.
I intend to keep the P3AT regardless, but I may replace the 40c with a 45c or other gun from time to time. I might throw in a 340 also but haven't given it too much thought. Anything I use will function pretty much the same, i.e. no safety, so I wont be thrown off by needing a different technique in different circumstances. I think this is essential in any carry system.