It varies, but I like my Ruger NM Blackhawk Convertible 4 5/8" with the ACP cylinder. With the alloy trigger guard/grip frame and ejector housing, it's very light for the caliber and carries well. With either the ACP cylinder or the .45 Colt cylinder it's scary accurate, and has all the power I want these days. A primo "packing pistol" if you will.
Way back when I picked up an OM Flattop .44 Magnum and had it bobbed off to 4 5/8". Nice gun, but it kept launching ejector rod housings. I finally had it rebarrelled but by then the NM Convertible was the go-to gun.
Have also fooled with a NM .357 Flattop, which is a nice gun but HEAVY. Tried a NM .44 Special Flattop but never could come up with a cast bullet load that wouldn't lead. So by default the .45 Convertible is it.
If I could ever find an OM .45 Convertible (again--had one and sold it) I'd
like to try it because of the simpler and stronger lockwork.