I'm gonna go against the grain.
The M10's are great, but Smith's Adjustable sights are just too good to pass up.
A M15 would be cool! Especially in a 6" barrel with Silhouette sights.
Although if you want something softer shooting, a 686 is great on the range, but a M27/28 would be like a Cadillac, very classy and comfortable.
A 3" M60 would make a handier packin' pistol than the M66 and would still be tolerable with magnum loads, and pretty fun with 38's. Compared to the alloy framed guns at least.
Something really different would be a 625. It's my favorite pistol that's not a M19! Definatley a range toy though. Although it would make a solid bedside gun.
Although if you want to stay with classic, fixed sighted guns... Look out for a M1917! The "M10 version" of the 625. Issued to troops in WWI, there's plenty on the surplus market and at decent prices. I had bid on a few M1917's and lost when I lucked into a good deal on a 625 locally and bit the bullet and paid a little more than a VG condition M1917 would have cost as the 625 was what I REALLY wanted.
I really like the 625, but I still want a M1917 to have around. I just might buy a beater and let my imagination and a gunsmith loose on it, but that's a whole different thread!