Haley Joel Osment started doing voiceovers, hit it big with Kingdom Hearts so I think he's relaxing with that. I don't think Jonah Hill is funny at all. He reminds me of redhaired Jack Black.
But for the list:
Males
Clive Owen - I thought his career was supposed to take off, but it really hasn't in the least. He was cool in Sin City, didn't like the International, and Shoot Em Up passed the time.
Seann Patrick Thomas - The black dude from Barbershop, Cruel Intentions and Save the Last Dance. I haven't seen him do much of anything in the longest while.
Michael Jai White - Yeah, I know he's been in Why Did I Get Married and the sequel, but I thought dude was going to be a huge action star or something along those lines. Sure Spawn sucked, but Exit Wounds wasn't bad.
Females
Julianne Moore - Seems she's everywhere, yet nowhere. The draw to her isn't huge at all, the Forgotten was sick, but I saw it for the movie, not for her.
Meagan Good - I know she's eye candy, but she should want better for herself and do more than she's done. Being the nerd's object of affection, or the girlfriend to a main character, to being killed in the first few minutes of a horror movie doesn't do her justice.
Kimberly Elise - She's been around so many good actors and actresses, including Oprah of all people, and has yet to blow up?? Not for nothing, but once you're around Oprah, everything you do should be gold (Precious).