My favorite is an old S&W M-17 with the 3-Ts; target trigger, target hammer, and target stocks. I bought one many years ago as a gift to my dad. It was one of his dream guns but never got around to getting. In later years he did not like the look of the newer ones and kind of gave up the dream. Finding a nearly mint one form the early '60s was a shock to him. For this reason it is my favorite.
every thing I own is a semi, with exception of a SW mod 10 in .30 that I captured in Korea, and a Ruger super redhawk .44 mag. So I guess it would be the .44. I don't shoot the Mod 10 a whole lot as it slips time on the cylinder and shaves lead.
My favorite caliber for the wheel gun? Gotta be the 45LC! It's been around a long time and it works! If it ain't broke don't fix it.
The Ruger Blackhawk is excellent for taking large game such as deer, handles well and has good balance. With the correct cylinder it'll shoot .45acp, which happens to be my personal favorite as that is what I carry on duty.
I'm just recently reunited with my old Ruger Security Six/.357, it's a 4" stainless steel model w/ Pachmayr grips. I picked up one load for it yesterday, Federal Premium 'Low Recoil' 130 gr. Hydra-Shok. 20 rounds for $15 + tax....ouch. At 75 feet from a standing rest I had a tight group of 3 (8-9 ring) & 3 in the 7-8 ring on a 50 foot target. Of course I touched those shots off single action.