I started with a 1911 only because it was my first handgun and I got my CCW at the same time. Very shortly thereafter I carried a P-22 because it concealed a bit better (had a better holster for it) and it was lighter. Then I got a colt pony pocketlite which was a great pocket gun, and it was summertime.
Then i found an old S&W Model 60 in .38spl., which to me was a better pocket gun for a lot of applications, and I carried that in the summer as well.
Then I got a hankerin' for a 9mm, so I got a Sig P239 in 9mm. Nice platform, carried it for 6 months till I realized that there were smaller guns that shot bigger bullets, so I sold the P239 and found a Colt Defender ( 3" 1911). That's what I carry now. I became totally sold on 45ACP as a carry caliber, and 1911 as a platform I like a lot. I just can't deal with the weight of a 5" steel one right now.
Also, in the summer my work uniform becomes khakis and a polo shirt, and it's tough concealing a 1911 in that, so I plan to go back to pocket carrying a j-frame. Looking into smart carry though to see if I can use that effectively.
I still carry the Colt Pony when just am going into town, or going skiing or someting in which a full sized gun would be hard to carry.