Amy Winehouse is a good singer and a very funky song writer, but obviously she's a total nightmare as a person. It's not all that surprising or unusal. Many, many talented people are morons, especially in their personal lives.
Faulkner, Hemingway, Steinbeck, Fitzgerald, Kerouac, Burroughs, Jim Thompson, Woolrich, Chandler, Hammett -- these guys were all talented writers, the best of the best, and they all either hurt their creative output or ended it completely because of booze.
But writers are solitary artists, out of the public eye for the most part, but drunk or coked-up singers are celebrities whose antics are news worthy and enjoyed by the public. That's why, I think, fucked-up singers die so much faster than fucked-up athors. Just look at the casualty list: Jim Morrison, Janis Joplin, Brian Jones, Elvis, Keith Moon, John Bonham, Syd Vicious, Kurt Cobain, Ol' Dirty Bastard, and so on.
If Winehouse is able to clean herself up, she might have one more good album in her -- one that records her struggles to get clean. But if she continues smoking crack and boozing wildly, she'll be dead in a couple of years and her record company will be releasing another compilation of her live and B-side tracks.
It's sad either way. You can't inflict that level of abuse on to your body and brain and come out of it as talented and as creative as before. With the black ugly hair and the pale, tatooed body, the woman looks corpse-like already. She gives off the same kind of vibe as the junkies you see on the street -- they're dead already, they just haven't fallen over yet.