If you haven't watched this video tribute to Dennis Hopper by Matt Zoller Seitz, from early April, you should. It's NSFW, because those are the kind of roles Hopper played.
What do I think about when I think about Dennis Hopper? The paranoid, offensive, hilarious and poignant biker Feck in River's Edge; Frank Booth, the most terrifying of David Lynch's gallery of demonic figures in Blue Velvet; his edgy turns in two Francis Coppola films, Apocalypse Now and Rumble Fish; his fractured alki in a film whose beloved status I've never quite understood, Hoosiers; of course Easy Rider; the despotic businessman in George A. Romero's Land of the Dead; and his unforgettable confrontation with Christopher Walken in the otherwise overwrought True Romance.
But I also think of, having grown up watching a lot of them on TV, his great supporting performances in notable westerns. The same year he made Easy Rider, he had a wonderful scene with John Wayne in Henry Hathaway's True Grit. And an even better cameo as that holy lunatic gunned down without mercy in Ted Post's Hang 'Em High (it's in the Seitz tribute). And another memorable part as James Gregory's weak son in Hathaway's The Sons of Katie Elder.
Hopper had been pretty much exiled from feature films after he had an epic confrontation with the same Henry Hathaway while filming the 1958 western From Hell to Texas; this ended the career momentum he'd built with good parts in popular films like George Stevens' Giant and John Sturges' Gunfight at the OK Corral. So Hopper went back to TV (where he'd worked on shows like Cheyenne): Naked City,Twilight Zone, Bonanza . . . and Petticoat Junction, as also excerpted in the Seitz tribute. But I guess Hathaway didn't hold a grudge--and he must have thought Hopper was a good actor, for him to bring Hopper back from the wilderness.
In these roles, Hopper had to make a big impression in a hurry. He always did.
UPDATE: The New York Times obit is now online.