I guess it depends on the purpose. Don't really know of a favorite that I don't own...................YET!
Since the kids come along I don't buy many anymore. But every once in a while I'll pick another one up.
As far as a duty gun. Glock 22. .40S&W
My summer wear hideaway. Keltec P-AT .380 ACP
Duty rifle. Bushmaster XM15. its an AR m4 type. .223/556 NATO
Dove hunting. Winchester 1200 and 1300. Yes I carry two.
Deer Hunting. Savage 110. 7mm RemMag. Wanting a Browning .25-06. One of these days!
After the first deer of the season is taken. S&W 629 8 3/8" brrl. .44mag
If hunting from the four wheeler. Marlin .30-30.....I forget the model...maybe 336?
Shooting for fun and squirrel hunting. Ruger 10/22.
My pride and joy. It was inherited. Winchester 94. .32-20, with hex brrl. Original not a repro.
Duty shotgun. Well we carry the Remington 870 12ga. Its OK, but they won't let me carry my Winchester anymnore.
My winter time concealed carry. Colt 1991 A1 Compact .45ACP and Rossi snubby .38 spl
Discussion builder would be the .32-20 and my other novelty a Springfield M6 Scout. .22 Hornet and .410 shotgun over/under.
Have a few others that haven't shot or even looked at in years.
If I could only have one. I would have to take the AR. As I know ammo will always be available and if WWIII ever comes I'll be prepared near and far as practical.