I agree with the choice of a .357 provided you intend to handload for it, and components are cheap and plentiful. If handloading isn't something that interests you, you had better start with a rimfire, and the Smith & Wesson M-17 K-22 would be a good place to start.
The selection of .357s is abundant, although I must admit a preference for the older style K and N frame Smiths (M-13, 19, 27 & 28) or the .41 frame Colts (Lawman, Trooper, Border Patrol,& Python). I also liked the old Ruger Security Six or the Speed Six, but I'm less happy with the newer Ruger DAs, to me they seem a little clunky. A Blackhawk is always a good choice, for the SA enthusiast, and it now comes in so many versions that its tough to keep track.