Depends on where I'm carrying.
Urban, S@W model 10 stainless chief's special or its Rossi clone. Most likely the clone.
Suburban, Ruger GP-100 with +P 38 in the chamber.
Rural, Same thing, but 6" barrel.
A 44 Ruger, likely a Redhawk, but I like my scoped Super Redhawk and Bisley Blackhawk too.
Location affects caliber and likely targets.