A tough question, 3 possible choices:
Most favorite is probably the gun I wear to work every day and most days off work, a stainless lightweight Colt Commander in .45 ACP, bought in 1997 to replace a very similar Colt Custom Carry Commander I'd bought 6 years before, and which had the forward portion of the slide snap off while shooting a qualification. The newer Commander has saved my life, and greatly altered a few others' lives.
If not the Commander, the favorite would be a Colt New Frontier single action revolver, 4-3/4 inch barrel, blue and case hardened finish, .44 Special chambering, to which I had Colt fit an auxiliary .44-40 Winchester cylinder. Walnut stocks, but someday I'll have ivory stocks installed.
The third possible non-S&W favorite is also a Colt product, an Official Police double action revolver with a 6 inch barrel, blue finish, checked wood stocks, chambered for .22 L.R. My dad's grandfather and my dad were finish carpenters, cabinet makers, Dad apprenticing under Granddad. This was in the 1945-47 era, when even in new housing subdivisions, pent-up war demand for consumer goods still caused many homes to have no telephone as yet. My Dad and his Dad were working out of town during the week building new churches, and came back home on weekends. Mom had just given birth to my oldest sister. A peeping Tom soon found out Mom and baby were home alone at night without a phone and began to frighten them as Mom got ready for bed. He got bold, knocking on the glass, scratching on the screens with his fingernails. Mom screamed, her neighbors would come but they never caught the peeper.
After a week or two of this, Mom told Dad and Granddad about it. Gramps went into another room and came back with a brand new Colt Official Police double action revolver chambered for the .22 LR round, and a handful of cartridges. He showed her how it worked.
A week later, the menfolk were again out of town, it was evening, and as Mom got ready for bed, the peeper returned. She screamed. He laughed and knocked on the glass. She grabbed the Colt and pointed it at him, and yelled for her neighbors. He laughed more loudly and clawed at the window screen. She pointed the Colt at the window with both hands and screamed and emptied the Colt through the glass at him. A neighbor with a phone called the police. Upon their arrival, the peeper could not be found, but they did locate a significant blood trail from the area of the window, which went up the driveway to the street, where it ended, possibly as the peeper then left in a car. She got him at least once, was the consensus. The officer conducting the investigation summed it up by telling my mother, "Lady, you gotta be careful wid dat ting."
All three favorites, all three Colts, all different reasons for favor.