I figure if I'm going to reply, there should be a bit of a story with each gun.
Colt Police Positive Special: My father bought this revolver for almost nothing back in the 80s. Since my parents were divorced, he gave it to me in my early teens to protect the family if necessary.
This revolver almost deserves two positions on the list, because 30 years later, after carrying an auto for many years, I broke out the Colt only to realize I shoot it better than the semis I have been practicing on for many years, which restarted my relationship with revolvers in general and led to me buying a bunch of S&W revolvers.
Browning's 1911: Some of my earliest recollections of firearms in movies are of the 1911. Fro some reason my most prominent 1911 memory is from the 1951 version of "The Thing". When he was about to open the door to confront this alien creature, he pulls out his 1911 and cocks it, which stuck with me for some strange reason. Not long after, I found a all-metal 1911 mock-up at a garage sale, and it became my favorite toy for the rest of my childhood. Fortunately, I never got shot while playing with it, because it looks quite real from a distance!
SIG P380: This one is what truly got me carrying a gun. I had long toted my (real) 1911 on road trips, but even after I got my CCL I didn't carry a gun on my person. Then about 10 years ago I stumbled onto the P238, and it lived in my pocket most of the time for the next 5 years. It was displaced by a S&W 637 after my rediscovery of revolvers, and lately my pocket gun is a Kimber K6S.
S&W Model 29-10: I got this a few years back, and it has since become my favorite gun. It was used and the owner had run about 10000 rounds of 44 SPL thru it, so the trigger is like glass. I have since shot another ~2000 rounds of light magnums thru it. I go thru phases where I carry it or the 3" M629 I got later. This is the gun that started me reloading, and I now reload the vast majority of the rounds I shoot in many different calibers. I recently got a Winchester Model 70 in .458 Win Mag, and I will never shoot a factory loaded round thru it, which is only possible because I bought that M29.
Browning's Hi Power: Since I started carrying full time, I have almost always carried a revolver. But after the attacks on US servicemen a few years back and some of mass shootings, I felt like more capacity might be a good idea. I bought a well-used Hi Power literally a couple of days before Browning/FN ceased production and prices skyrocketed. This gun has proven to be flawless and I shoot it better than any auto I own. I carried it almost exclusively for a couple of years. These days this is the gun I carry when I'm feeling more paranoid than usual or going to the movies, but lately I'm back to carrying my M629 most of the time.