The classic Colt Single-Action Army
Of course the iconic sidearm of the West has a place in my collection, and I intend to add at least two in time. Chambering in .45 Colt or .44-40 Winchester Center Fire (the more popular of the two in the period) is period-appropriate, but I'd rather go for .357 Magnum or .38 Special for one and .22 Long Rifle for the other. For my purposes, these are guns meant for recreational usage; I can use them defensively, but I have more modern options for those roles (and if you're familiar with this model of handgun, you know why).
The New Model No. 3
But, of the popular revolvers of the era, the top-break Smith & Wesson No. 3 is what I would rather carry. Historically chambered in cartridges that aren't readily available anymore, contemporary replicas include options for .38 Special (though I would prefer .357 Magnum) so that's what I would add. Alas, a .22 Long Rifle model is not available. The purpose is the same as above; carry is a tertiary purpose, as I'd rather have something more contemporary for that.
If you're gonna carry a revolver, it's likely to be one like this.
When it comes to contemporary revolvers folks like to carry, a snub-nosed revolver is most common. Both Colt as well as Smith & Wesson dominate this, but none moreso than Smith & Wesson nowadays. The pic above is from the Bodyguard line, specifically Bodyguard 38, but I'm eyeing the 649. (Not that I will complain about getting any model in this line.) I want the option to fire in Single-Action, as this model allows. Others are Double-Action Only by removing any bit of the hammer from external manipulation, and some don't shroud the hammer (as the Bodyguard does) which limits its carry effectiveness.
Most service revolvers look something like this.
The only other revolver I'm looking to add is what is termed a "service revolver", as it formerly was the sidearm of military and law enforcement personnel world-wide. With barrel lengths between three and four inches, these are not that concealable, but can be with some forethought; for my purposes, this is something I use as a home defense backup arm (backing up a shotgun or rifle).
The Smith & Wesson Model 19 pictured above is in .357 Magnum, which is ideal due to its ability to also use .38 Special; acceptable would be a Model 10, a Model 13, a Model 15, or their stainless steel counterparts (Models 64, 65, 66, and 67) as they are in .38 Special or .357 Magnum- both widely available cartridges capable of pairing with a lever-action rifle or carbine chambered for the same cartridge.
(Yes, I'm aware of Ruger's offerings; they're fine, even preferred in some instances. No need to tell me so.)