My choice is the .45 Colt. If you are a reloader you can make just about anything you want.
I really don't have a feel for what you would find in the shelf as I don't buy factory ammo.
My experience in locating .45 Colt ammo when I first bought mine was that factory ammo comes in two flavors. Poofy whiffleball loads for the cowboy action crowd with SAAs and their clones from the usual suspects, and heavy-hitters from the likes of Double Tap, Buffalo Bore, Cor-Bon, HSM and Grizzly Cartridge for the Ruger and Freedom Arms guns used for hunting and protection from large predators.
There aren't any factory loads in mid-range bullet weights and velocity to my knowledge. Factory .45 Colt also seems to be the most expensive revolver ammo out there when you take the S&W howitzer cartridges out of the mix.
To get the most out of a .45 Colt or even a .44 Special, you need to handload.