Favorite for what?
For concealed carry, I like my 640-3. Don't mind scuffing up that IL equipped lead spitter. It's in a Kramer pocket holster with a speedloader next to it, and it's good to go.
For sweet shooting, give me the old RM with a 4 inch barrel, please.
I think that if I had to carry in an open holster for social events or for a secondary weapon for hunting or for wandering around in the boonies, I would want a 627 with again, a 4 inch barrel. And 8 shots, please.
If I was to use it for actual hunting, again I would probably want a 627, but with a longer barrel, of course.