To me, Patrick Stewart is no longer stuck as Cpt. JL Picard, after his role as CIA director Avery Bullock in American Dad. He is such a goofy irreverent pervert as Bullock, it completely destroys his stolid no-nonsense starship captain role. I wonder if he can make it through a reading without cracking.
The first movie I saw Hugo Weaving in was “Priscilla, Queen of the Desert”, a few years before “The Matrix”. Re-watching Priscilla, during the first scene when he is putting on makeup and wig, all I could think about was, “That, Mr. Anderson, is the sound of inevitability.”
Sean Bean is always Richard Sharpe.
Ed O’Neill is Al Bundy.
What’s weird about Katey Sagal is that her voice is always Leela from Futurama, but her look is always Peggy Bundy.
So unless I’m watching Futurama, I always have some kind of dissonance going on- especially on something like “Sons of Anarchy”, where I hear Leela, and see Peggy Bundy and she’s playing an completely third character.
^ Katey Sagal is EVERYWOMAN!
(Katey, are you out there? Katey?)
Michael Shanks is always Dr. Daniel Jackson. This fact made his appearance as Victor on Burn Notice pretty funny for me.
Same for Tricia Helfer; she’s always going to be Cylon No. 6, even if she did do 8 episodes as Carla on Burn Notice.
Brian Blessed is forever Prince Vultan, the Hawkman leader from Flash Gordon.
I dunno. Denny Crane was sufficiently unlike Kirk that it broke the association for me. (And the Priceline Negotiator is sufficiently like Denny Crane that I can now look at Shatner as being, well, a guy playing different roles.)
That’s cool. YMMV as usual. I never saw much of that show, so he’s still Kirk to me. My brother is getting to look more and more like him, too, so that adds some weirdness to it.
As long as he’s not Evil Kirk from The Enemy Within. 
Mnemonic: Since their full names have only one s each, you can prevent accidentally using the wrong last name.
Christopher uses an s, so he is Reeve.
George does not, so he is Reeves.
It was the difference of the Big S (think Superman’s logo on his unitard) that had never struck me before. I had their names straight enough. But two actors playing the same character with the same surnames – except for an S – never had made that connection for me before. 
Yeah, but tons of people don’t have their last names straight, so I try to share that mnemonic whenever I can.
Have you… met my brother? :eek:
-
Brian Dennehy as Will Teasle in “First Blood”
-
Terry O’Quinn as John Locke and Michael Emerson as Ben Linus, from “LOST.” (I’m trying to buy Emerson as whassiname on “Person of Interest” but it’s been a real struggle.)
-
Michael J. Fox as Alex P. Keaton from “Family Ties” (and possibly Marty McFly). Actually, he just kinda plays “Michael J. Fox” regardless of the movie…
-
David Duchovny and Gillian Anderson as Mulder and Scully (“X-Files”)
-
Jake Gyllenhal as Donnie Darko
-
Peter Krause as Nate Fisher from “Six Feet Under”
-
Wes Bentley as Ricky Fitts in “American Beauty”
-
Brendan Gleeson as Hamish from “Braveheart” (and I feel bad about it, because Gleeson’s such a great actor and that’s not nearly the best of his performances… but… can’t… get it out… of my…head…)
Side note: Actually, I’ve been really shocked and happy with Mads Mikkelsen as Hannibal Lecter on NBC’s “Hannibal.” Brian Cox wasn’t very evocative as Lecter back in “Mindhunter,” but Hopkins had such a lock on the part, so I was so surprised at how good Mikkelsen is… but of course he has made the part his own rather than trying to emulate Hopkins.
He’s nearly 80 and this was going on 35 years ago, but Jack Nicholson will always be the batshit crazy Jack Torrance.
On the distaff side:
Rosalind Russell will always be Mame
Judy Garland will always be Dorothy from Wizard of Oz
Nastassia Kinski will always be Irina from Cat People
Kathleen Turner will always be the femme fatale from Body Heat, except of course when she’s Chandler’s dad from Friends.