A good suggestion. I’ve seen a few people doing impressions of Tracy Morgan, so I think he’s become an established stock character for impressionists.
It differs in that it’s a impression of Heath Ledger. 
Do you have any links? I’d like to see that.
Frank Caliendo’s Pacino is really good (to me):
Sorry…Pacino never happens in that link. Still hilarious though. Follow my other link for kick ass Pacino and DeNiro…
Frank Caliendo is good! I was thinking that Russell Brand has a distinct presentation that could be imitated and recognized.
Looking at Fandango’s survey of top 10 favorite actors of the 2000’s (Johnny Depp, Denzel Washington, Robert Downey Jr., Matt Damon, Russell Crowe, Leo DiCaprio, George Clooney, Hugh Jackman, Brad Pitt, and Will Farrell), only Denzel and maybe Clooney have a distinct voice and delivery.
I think Depp does but it’s mostly due to his role as Jack Sparrow in the POTC movies. Also, Russell Crowe–with his short temper, humorlessness, and pretentiousness–is a ripe target but, to my knowledge, has only been lampooned on “South Park”.
Anyway, if we’re talking old school actors, people like the late Paul Newman and Robert Redford were or have been famous for years but I have yet to see anybody even attempt to do an impersonation of them. Especially in the case of Newman, I thought he had enough mannerisms and memorable roles (e.g., The Hustler and Cool Hand Luke) that would’ve got somebody to do a good impersonation. However, during his whole career, he was one of those few iconic actors who was seemingly impressionist-proof.
Here’s Kevin Pollak attempting it, though he recognises he’s not there yet.
Here’s another guy who’s closer, he has that blocked nasal thing down at least.
Jimmy Fallon does a dead-on Adam Sandler impression.
And his Jim Morrison is spectacular too.
That is fucking awesome!
I haven’t watched SNL since John Belushi died, so I missed that. Although a buddy and I, huge Cage fans from way back, will occasionally, out of the blue, say to each other… “FUUUCKK Mexico!” (Red Rock West) in our best Nic explosions.
I do impressions of Jeff Dunham’s puppets. My family thinks my Walter is hysterical. But I’m still not ready for primetime.
I don’t have much to add to the OP, but on the subject of impressions:
*Rich Little has a variety show in the late 1970s. At the end of it, he would invite audience members to ask him to do impressions of celebrities that were not part of his normal shtick (John Wayne, Johnny Carson, Jimmy Stewart, etc.). I remember once an audience member called out “Merle Oberon!” Rich kinda chuckled, saying “Merle Oberon!” and went on to someone else.
*In my opinion, I thought David Frye was a much better impressionist, but never had the success that Little did. I guess you could say Frye had little success, but not Little’s success.
OK, end of hijack.
Miles Fisher.
Now that’s even more frightening than the real Tom Cruise.
Regarding Walken, I never heard anyone attempt an impersonation before Jay Mohr did it on SNL (Skittles commercial). Maybe he’s not the original but he slamdunked it there.
I found it annoying and didn’t watch much longer than it took to see that the job was up to snuff.
It’s not hard to find impressions of young actors. A woman has a series of videos on YouTube called Hey! The Zooey Deschanel Show but I have no idea if she sucks or not. Actually, she just said something funny, (“Look out! He has a gun and a baby!”) so she doesn’t completely suck. I don’t know if she really sounds that much like the source, due to unfamiliarity.
Naturally, there were links to other young women who do impressions, but they seemed to mostly be (bad) singing, until at last, I found one I liked-- no singing at all, although not all the impressions are spot on. Nickelodeon Impressions - YouTube
I’ve seen a couple of Robert Pattinson impressions (the affected vampire from the Twilight movies) around.