Geez, that question covers some ground... all the way from a .22 lr single six to Ruger's latest offerings in Flat Top configuration Blackhawk .44 Specials...forced to pick just one, I'd opt for my 4-5/8" .44 Special BH Flat Top...tho a close 2nd would be a S&W M57 purchased new in 1972. Both are equally accurate, and probably equally deadly in real hand gun terms as well.
I'd waited for a .44 Special for 40+ years, having grown up on Keith's and Skeltons writings back in the 70's. Then, a true .44 Special was only available in S&W's 4" and 6" Model 24's. Skelton had one built up on a S&W Highway Patrolman Model 28, but at a fantastic cost of $125 plus the price of the gun, and a six month wait from the arrogant gunsmith who was doing the reboring and rifling necessary...and with no guarantee on how it'd shoot. (My first encounter with celebrity gunsmiths who's work was trumpeted in the gun mag's).
So I waited, 40+ years...and Ruger finally came through...when it came in to my LGS, I felt like I was ten years old again and opening my first BB gun under the Christmas tree.
To date, that 4-5/8" is my most accurate hand gun...loading for it is ridiculously simple...most any reasonable combination works...here's a pic...good luck finding your "best ever"....and hope you all don't have to wait the forty years that I did.
Best Regards Rod