Currently the New Model Vaquero in 45Colt. They really work well for me. Unfortunatelt the big batch of Winchester cowboy ammo is a bit off, not as good in these guns as the old MagTec stuff. I have huge hands, but strangely enough, I accidentally 'slipped' the hammer a lot more with the old model and my NMSBH. The Colt sized grip seems to work better for me, go figure?
I love the 45 and really like the way I can just chuck the rounds into the cylinder, the chamber opening is so big, there is nothing to catch up on, they just fall straightin with a satisfying schloooooNK!!!
Having said that, I have bought new guns, all in 44WCF (1873 rifle as well) as I intend to start shooting classic cowboy and will convert to black powder when I have got on top of the muscle memory required for the new discipline (one learning curve at a time thanks).
The guns are Piettas in 44WCF 4 5/8" Bbls with an action job. They are sweet, but I haven't competed with them yet. I won't be getting rid of the 45 NMVs until the clones prove themselves. If they work out all right, I have a NIB 44WCF Dakota clone, I will get it slicked up and use it as a back up gun.
Strangely enough I saw my 44Mag Old Model Vaquero in the gunshop I traded it in for the NMVs. Big bores don't sell well here, as they require a special permit (easily obtained, but most shooters don't bother, which I find strange). I am in two minds whether to buy it back or not, I have up trying to find a mate for it and traded it on the pair of NMVs mentioned above. It needs a good home, but apart from being my first SA it doesn't have many other redeeming features, I have an older Blued 44Mag SBH with the long barrel (10" or something like that) and a 44Mag SS/NMSBH in 5 1/2" so I'm pretty well fixed for 44s.
Decisions, decisions!