Personally, I usually either carry a 1911, a Glock, or a S&W 36.
I carry either the 45 ACP Combat Commander I built or my 3 inch 44 Special revolver most of the time,but in real hot weather when I am wearing shorts and a light t-shirt I carry the Kel-Tec. As you pointed out,it has a clip built right on the side of the pistol that can be used to clip it to the inside of your waistband,and nobody will ever notice it under a t-shirt.