G.W. Bailey, whose last (maybe only) likable role was as Luther Rizzo in MASH*.
I love watching GW Bailey in The Closer. Plays a very likable cop. Kyra Sedgwick is his boss.
But, you’re right. He’s also played some nasty, jerk characters too.
Ladies and gentlemen, it is my mixed pleasure to present to you a man who can play an asshole like no one else: Dan Hedaya! Dan has played dozens of pricks and a-holes over the course of his 40-year career in film and TV, including recurring TV roles as a dirty cop in Hill Street Blues and as Carla’s husband Nick Tortelli in Cheers (and in a shortlived spinoff, The Tortellis); while in the movies he’s been Bette Midler’s ex in The First Wives Club, the general in charge of the doomed xenobiology lab in Alien: Resurrection, and the titular prick in the movie Dick, in which he played President Richard M. Nixon.
William Daniels: Dr. Mark Craig on St. Elsewhere, John Adams in 1776, two different a-holes on the Rockford Files, the list goes on.
He was also the prick boss , Mr. Waturi , in “Joe vs the Volcano”.
I didn’t try to list them all (he’s got 120 listings on IMDB), 'cause that would be, you know, a dick move. 
I always thought that whenever Jerry Orbach wanted to play an asshole, he could REALLY play an asshole. I think it was the timber in his voice. He could have a slight tint of contempt added to the colour of his voice when he wanted to, and a twitch in his eyebrow that said: “I’m such an asshole, I bet you want to slap the smirk off my face.”
I miss Orbach. 
John Vernon, whose best known role was Dean Wormer in Animal House was long typecast by Hollywood as being a shady character in numerous movies.
Before going Hollywood, he played a crusading coroner in the CBC show Wojeck, the idea of which was stolen to become Quincy with that whiny Jack Klugman.
Gary Cole, played Lumbergh in Office Space. Also played the asshole boss in One Hour Photo, the douchebag crime boss in Pineapple Express and an abusive husband/asshole cop on Desperate Housewives.
He chewed the scenery as a Latin American dictator in “Commando.”
Life does not imitate art in this case. Bill Daniels and his wife Bonnie are two of the nicest people I have ever met.
And Buck in American Gothic, where he really might have been the devil.
Quite a few pop into my mind:
[ul]
[li]Joe Flynn played Capt. Binghamton in “McHale’s Navy”, Dean Higgins in three Disney movies (with Kurt Russell), various corporate a$$4013s in other Disney movies.[/li][li]Scottie MacGregor and Alison Arngrim played Harriet and Nellie Oleson on “Little House on the Prairie”[/li][li]the aforementioned Larry Linville as Maj. Frank Burns on “MAS*H”[/li][li]Jack Colvin as Jack McGee on “The Incredible Hulk”. It still pissed me off that he was the one who started the lab fire that killed Dr. Elaina Marks, but he blames the Hulk.[/li][/ul]
It’s kind of unfair to quote that Burt Reynolds anecdote without including the very next sentence: “McKinney told Maxim magazine that all Reynolds’ stories were untrue. ‘If you lose control on a movie set,’ McKinney told Maxim, ‘it’s not acting, it’s indulgence.’”
(And pseudotriton ruber ruber beat you to the prick joke, although it was subtle.)
Speaking of Die Hard, no hate for Paul Gleason (a.k.a. Principal Vernon)?
David Warner was a prick in Tron, Time Bandits, and Titannic, just for starters.
I always thought his eyebrows had a lot to do with that. He pretty much looked like he never believed a word anybody was saying, and when wasn’t saying as much, you figured he was thinking it. Here’s a YouTube clip of him playing Billy Flynn from Chicago. The quality is poor but the contempt and the phoniness would come through in any medium.
Much of the cast of Homicide: Life on the Street. Richard Belzer, Yaphet Kotto, Reed Diamond and Giancarlo Esposito to name four. These guys are not heartthrobs in any of their film projects.
Time After Time also- hell, he was freakin’ Jack the Ripper!
I’ll see that & raise you Forrest Tucker.
Pun intended!!!