what defines good writing?

a couple of weeks back, i got into a mini-argument with someone who said that he felt Kurt Cobain wasn't a good writer. i am very biased in such an argument, because i happen to be a fan of Kurt's. yes, he was a crack addict who couldn't handle his life and chose what seemed like the easier way out. very few people know about the other side to his life, that he was plagued by stomach ulcers and couldn't eat anything for years and years.. its not a wonder he was emaciated and pallid, a steady diet of alcohol, painkillers and dope would do that to anyone. but i digress.

what makes a piece of writing good? is it some sort of alliterative rhyme that makes it melodic? is it the vivid use of words that describe emotions? is it the stark honesty behind it that strikes a chord? is it just the fact that it simply relates to something you feel or have felt?

after all, what are words? aren't they just keys to the soul of a reader, much like beauty lying in the eye of the beholder. what defines good writing?