Oh, boy. I'm gonna take some *major* flak on this one, but here goes:
Sean Penn (I think he's vastly over-rated. Sorry.)
Nick Nolte (All he does is Variations in Yelling.)
Al Pacino (See Nick Nolte - he was still good up until about "Sea of Love," then the Yelling began.)
Matt Dillon (He has one expression: Mad.)
Gary Oldman (He was great, then he let himself get typecast and just phoned it in for his next, like, 10 films. He's started to redeem himself with "Batman Begins," though.)
Daniel Day-Lewis (Ducking. I just don't get what's so great about him. The *only* movie I've ever seen him in where I couldn't see him acting was "In the Name of the Father.")
Sarah Jessica Parker (I can't stand her shrillness.)
Ben Affleck (The only one I could ever stand him in was "Shakespeare in Love," and that's because he played the perfect horse's ass - I'm thinkin' it wasn't much of a stretch.)
George Clooney (I'm sick to FREAKIN' death of him. And could he be any more of a shameless narcissist? Never have I seen someone so painfully infatuated with himself.)
Now... Lemme take off the gloves...


Now its my turn to say amen sistah... And I'm still laughing about the liberty you took in creating a whole new "Style" of acting - the "Yelling". LOL I LOVED Al Pacino the Godfather part I & II (you see the innocence lost in his eyes, its magic, he did such a good job) and I tried to hard to like Scent of a Woman and I hardly got the message because I had to turn up the volume on the TV to hear Chris O'Donnell's dialogue and then rush to turn it down as soon as it was Al's turn to talk. With all the fumbling of the remote, I pretty much missed the nuance of the film.

Matt Dillon = Crash. Nuff said. I only ever liked him in "the Outsiders" and we all know how long ago that was.
Daniel Day-Lewis. Oh gosh, could this man be more desperate to be today's answer to Marlon Brando?
I will add the following, seeing as how all the ones I would have picked have already been said:
Tim Allen (what the hell was that Shaggy Dog shit?)
Jennifer Aniston (just don't like her, sorry)
Jude Law
Calista Flockhart (eat an effing Tim Tam please)
Any of the I've-Pouted-My-Way-Into-This-Movie-Role-Posse: Estella Warren, Kiera Knightley, Beyonce Knowles, Heidi Klum et al.
And I try hard to like his movies cause I thought he did a wonderful job in "What's Eating Gilbert Grape", but I'm also gonna add Leonardo di Caprio..