I can't nail down 3 "favorites", since I have "favorites" for many different uses......
But I guess I'll choose my .45 ACP Vaquero, 9mm Blackhawk,and .22 SP101.
Of all the guns I own, these are 3 that are impossible to put down at the range, if I have ammo, I just keep shooting them.
A double action .22 is lots of fun to shoot and "stretch out" a range session, I can't always pop away with 400 rounds of .45 ACP but I can have fun and burn up a brick of .22 LR in a couple hours and still have a blast.
My 9mm Blackhawk lets me shoot a single action in the same power range as .38 Special +P but at 1/2 the cost, and my .45 ACP Vaquero is just plain cool, very accurate and shooting big .45's out of a thumb buster is loads of fun. And I can't afford to shoot that much .45 LC, also have other guns in .45 ACP too.
These are the guns that always find their way into the range bag, as long as I have "range ammo" to shoot, these come with me.
I would have thought it'd be more difficult to pick a top 3, but it was a lot easier than I initially expected:
My favorite individual firearm of all time, quite likely my most endeared earthly posession - Ruger Mark II 6" taper .22 Long Rifle.
My most dedicated game killing revolver, she looks very different today, replaced the mount with a Leupold dual dovetail, bisley grip, carbon fiber shingles, bisley trigger, NV crescent ejector rod, and a bit of elbow grease over the finish - Ruger Super Blackhawk 7.5" .44 Magnum.
Finished up by what I consider to be my best handling, most versatile hunting revolver that I own, very slicked up, and looks a little different now, but you get the idea - On the left: Ruger Super Redhawk Toklat 5.5" .454 Casull.