I generally find Seth Rogen insufferable, but I liked him in This is the End, and his voice work (In Kung Fu Panda and Monsters vs Aliens) is good.
I can’t stand Demi Moore, but I liked GI Jane. I’ve been in the military, and while I’ve never been a Navy Seal, I can see it being like that, just based on what I experienced in Basic, and OTC.
I’d echo this, except with Leaving Las Vegas subbed in.
I can’t stand Reese Witherspoon, but she was terrific in Election and Freeway.
I can’t stand Robert Downey Jr., so it was nice to see him get shot in Natural Born Killers.
Keanu was born to play Theodore “Ted” Logan, period. End of sentence.
My respect for Leo took a quantum leap when I saw him in What’s Eating Gilbert Grape? It took some time before it sunk in just who I was watching on screen.
Matt Lillard. The guy was seriously phenomenal playing Shaggy in the live action Scooby Doo movies. If you think I’m kidding go check it out. Easily the most accurate live action representation of a cartoon character. Period.
I never cared for John Wayne. I liked a handful of the movies he was in, not because of his appearance in them but despite it. For the longest time I couldn’t believe he ever won an Oscar. Then I finally saw his Oscar-winning performance in the original True Grit. It was like he was born to play the part of Rooster Cogburn.
I beg to differ about Cage.
Are you forgetting he won a Best Actor Oscar for his role in "Leaving Las Vegas?"
And he was hilarious in "Raising Arizona."
And…in Moonstruck.
Just my two cents.
A number of people on this board hate Steve Guttenberg. For them, I recommend The Boys from Brazil, in which he appears for a few minutes, then dies violently. 
Cruise was also excellent in “Collateral.”
He’s good in everything, really. His personal life is much made fun of but he is a fine actor. Most of his movies are fluffy, but when asked to carry some weight, he delivers.
I always liked his Oscar speech; “If I’d have known that I would have put that patch on 35 years earlier!” It’s a short, warm, and humble speech, rather unlike his screen persona.
Wayne might actually have been even better in “The Shootist,” which IIRC was his last film.
Generally not a huge fan of Sacha Baron Cohen in his own movies, but he was great in Hugo
Also toward the end of his career, he was very good in The Cowboys (1972). Of it, he once said (from my memory) “It’s the only movie I’ve ever reacted in, instead of acting.”
It’s been 40 years since I last saw The High and the Mighty (1954), the grandpappy of all Airplane-type movies (it even had Robert Stack in it), but I seem to recall he was very good as the pilot in that, too.
One fairly obscure movie in which I thought he also gave a good performance was Howard Hughes’ Jet Pilot (1957), in which his co-star was Janet Leigh as a Russian officer who defected to the US in a plane that looked remarkably like a T-33. Maybe not an Oscar winner, but definitely a fun flick to watch in bed with your SO late on a Saturday night. :o
Cameron Diaz is mostly a shit actor, annoying as hell, but I thought she hit the right note in A Life Less Ordinary.
Keira “The Jaw” Knightley is almost unbearable to me (though she is quite beautiful when her mouth isn’t moving)but she was terrific in Atonement.
I hate Will Ferrell, but really enjoyed Stranger Than Fiction.
I liked Will Ferrell in Elf, but generally can’t stand him but he was perfect in Stranger Than Fiction.
Nicolas Cage can be quite good in some rare occasions or among the worst which sadly is more likely. I liked him in Moonstruck, though not great acting, just competant for the role. Same for the National Treasure movies and Con Air. I though he was excellent in Guarding Tess. Then there are about 20 films starting with **Vampire’s Kiss **where he was terrible.
How did Neil Diamond record “Brother Love’s Traveling Salvation Show”? It sounds like him, and I love it, but it is not his usual style.
And while the songs in Starlight Express are fair to middling at best, as critic Michael Walsh wrote “One Rock and Roll Too Many” sounds like it wandered in from another show."
How about Crystal Gayle on the “One From The Heart” soundtrack?
Mark Wahlberg in Boogie Nights, and Bruce Willis in Pulp Fiction.