Donald McClarey has a fine tribute here.
I grew up hearing about him because he was a favorite of both my Mom and Dad. They were not big fans of many of his contemporaries or those from the Golden Age; them not liking Bogart, John Wayne, or Edward G. Robinson to name a few. But they liked Douglas, and I think it's fair to say he was one of their favorite actors.
As a result, and as a result of the movies that made their way onto the television when I was growing up, I got to know several of the films that made him famous. Top of these was, of course, the epic Spartacus. I also saw him in war movies, such as In Harm's Way, as well as later fare like The Final Countdown. I also remember seeing him in a strange movie called There Was a Crooked Man, and realizing he was the same fellow from Disney's 20,000 Leagues Under the Sea.
But I must say he was one whose presence far exceeded the films I saw. He had quite a large resume, and over the years I would see more of his acclaimed work, such as Paths of Glory and Lust for Life. But even with a fairly small number of his movies I actually saw growing up, his name loomed large in my upbringing, again because my Mom and Dad were such fans.
I remember hearing that he was not happy about his son Michael being in some of the racier scenes in Fatal Attraction and later in Basic Instinct. Nonetheless, whatever estrangement they may have had, in later years the two became close, and Michael emerged as a major defender and champion of his Dad's long legacy.
So RIP Mr. Douglas, you gave the world a body of work we will enjoy for years go come. You also handled yourself with a maturity and class long lost in our own troubled age. You represent the better parts of what we've lost. May God's peace find you in the hereafter, and His grace and strength be given to your loved ones and all who remain behind.