Was this guy particularly good in his roles?
Good question. As best I can recall he was at least convincing as the character in that if he was menacing or sneaky or up to no good then the character was supposed to be that way. Whether he was just cast to type is harder to say until I can look over his list of credits. It’s obvious the guy was not all that “memorable” wouldn’t you say? 
Let me try an example. Before I knew much about Brad Dourif and had seen him in maybe one or two roles before Cuckoo’s Nest (yes, I zoomed in on your username) and possibly even the Laura Mars thing, I was anxious to know his name and went to the trouble of learning it. Since then, Dourif has done some memorable work and I can’t think of anything he’s done that I don’t think was a good job of acting.
This guy is not as striking as Dourif. He’s not even as striking as Jake Weber and Linus Roache. For somebody who went to the trouble to learn the names of old B Western guys like Roy Barcroft and Lane Bradford, you’d think this guy just slipped through the cracks.
I’m going to be really pissed off if he wins and Oscar in the next few years! I’ll be surprised if he’s had lead billing in anything, too. He doesn’t even strike me as good sidekick or partner material. I just want to know the guy’s name – not marry him!
This intrigues me. I can’t come up with any other prospective names, though; we’ve already been through all the ones I can think of. Unless… is it Rufus Sewell? http://eur.i1.yimg.com/eur.yimg.com/xp/premiere_photo/20051024/10/4210572315.jpg
Rufus Sewell has some features in common with my guy, but the tricky eye isn’t one of them. I like Sewell a good deal and have seen him do some good work. You can even add Sewell to the Roache/Weber look-alike gang if that helps conjure up another face in that quadrant.
Ron Livingston played a role very much like this in the film Pretty Persuasion in 2005.
Livingston’s starring in the short-lived series Standoff as well as his Office Space and Band of Brothers roles makes his recognition factor significantly greater than Mr. X. As far as appearance goes, Livingston is much darker than Mr. X.
Is it Brian Thompson?
Not the one. Age appears to be about right but the skin texture is off.
Michael Emerson He’s had longer hair in a few things. (I don’t think he’s been named yet. I did do s search of this thread.)
How about Andrew Divoff
This one picture is tantalizing in that the eyes are in the range of how I remember Mr. X’s eyes. The hairline isn’t right in the picture, but with longer hair that might be less an issue. The features in common with Weber are closer than any others so far, but less so with Roache.
A further search for pictures at Yahoo! Images brings back none I can feel any more comfortable with, so I am saying I’m 90% sure this is not the man I’m trying to find.
Not him, either. Again, the skin texture is wrong.
TDoes the guy you’re looking for look a bit like a younger Brent Spiner? (Data from Star Trek)
I’m going to say “no” on the Spiner resemblance, and that’s after looking through the IMDB gallery for him.
However, as far as resemblances go, I’ll add this picture of Michael Emerson (thanks to Swallowed My Cellphone) to go with those I posted earlier for Weber and Roache. Fusing these three photos gets as close as I have been able to so far.
Heh, my first guess was Michael Emerson.
How about Brian F. O’Byrne?
David Sutcliffe? (Don’t be fooled by the perm in the main shot; he’s had a variety of hairstyles.)
I’m going to throw out some more names in the hope of getting this search going again - because now I need to know too!
John McGinley? He’s a household name to fans of Scrubs, but to most other people he’s a “that guy” character actor who appears in everything but whose name always eludes memory.
James Remar? Another one of those prolific TV and film actors who’s still fairly obscure.
Jason Isaacs. Most famous for Harry Potter, but he’s been in a lot of other stuff too.
Hope we fucking figure this out.
Or James McAvoy?
Not the guy. The jaw is too narrow and my memory of Mr. X has his facial skin being clear of blemishes. This memory may be faulty, I admit, but O’Byrne’s heavy brows aren’t right either.
Thanks, The Scrivener, but David Sutcliffe isn’t the one, either.
Argent Towers, I’m happy you’re wanting to help the search continue, but I’m sorry that it’s not John McGinley, James Remar or Jason Isaacs. Reasonable tries, but they’re much better known, at least to me, than my mystery guy.
And GuanoLad, it’s neither James McAvoy nor James Purefoy.
Many thanks to all who have provided guesses. I keep hoping to come back to this thread and find that somebody has been able to name this guy by now. Sadly, his fame and recognizability are even less than I had imagined. Either that or he is very forgettable.