This has somewhat degenerated into the "My Favorite Pistol" theme
I'll have to agree with the Government Model.
It isn't the most common encountered, nor is it the best selling. It is, however, the single pistol that embodies the idea of "American". At least currently. The SAA has to be a close second or third and the 'police revolver' (either a S&W Hand Ejector or a Colt Police Positive) would be the other close second or third.
Interesting; the Colt SAA was not the best selling handgun of the 'frontier' era. There were far more S&W break tops in various models than Colts. I think I recall reading there were more S&W rimfire revolvers sold than SAA revolvers. (I could be wrong, but it sounds right.)
The police in the U. S. were staunchly revolver users from when revolvers were available until the middle 1980s or so. Yes, there were some departments and more individuals who carried an autopistol of some sort, but the vast majority were revolvers; largely Colt (which cost a bit less and brought up memories of the SAA) and S&W (which cost more and had a longer service life.)
And during the period from the end of the Civil War until the 1940s or so, were outsold in quantity by Iver-Johnson and Harrington & Richardson break tops. They were both cheaper and served well for the purpose at hand.
But I'll go with the Government Model. It is just 'American'.