Lots of good pistols mentioned. I own Ruger Mk2's and Mk4, S&W Victory, S&W 617, 317, 63, and 43 pistols and revolvers.
As a personal recommendation I'd avoid the Ruger Mk3 series, the slightly difficult reassembly process of the Mk2, with the added frustration of a magazine disconnect thrown in. The Mk4 is a dream to take down and reassemble. The reassembly is not difficult once you've done it a few times, but the Mk4 eliminates any difficulty at all.
I slightly prefer the S&W Victory as It's a nice handling pistol, but as mentioned, what fits me might not fit you. Aftermarket grips, triggers etc. are easily available from Tandom Kross, Volquartson and others. The Victory has a magazine disconnect, but it's easily removed if that's your choice.
Buckmark is also excellent though I've never owned one but have shot them many times.
I'll mention that the Rugers have their serial numbers on what most would call the barrel, or upper receiver. That makes a difference if you choose to change barrels at some point as it's an FFL item. Barrels for the Buckmark and Victory are buy through the mail items.