I'm all for the 686 also. But then again, I might probably go for a S&W model 29 in 44 mag. for stopping power.
If you gotta have one gun, and no set mission for it, I guess I would have to go for the best all around cartridge, the .357 mag.
So that leaves me with finally choosing the S&W model 27. All around cartridge, reliable as heck, and heavy enough to dampen recoil. It also fits my hand sooo well.
Close, call, there, to go 357 or 44...