Big call
How does Kurt Cobain not belong on that list?
Also, gotta laugh at the 3 rappers on the other list.
Stretch - Rapper - Shot
Fat Pat - Rapper - Shot
Freaky Tah - Rapper - Shot
Ahh, the good old days. 
I just don't think Nirvana's music will stand the test of time like the other guys on that list.
Hendrix did stuff with a guitar no-one had ever heard before, Dennis Wilson and The Beach Boys pioneered some incredible recording techniques with Pet Sounds in particular, Janis Joplin had an insanely unique voice (and to get back on-topic for a second, Amy Winehouse is probably one of the only female singers since to nail a similarly unique, bluesy voice) and The Doors, well, not much needs to be said about how awesome they were, but there has been no band since that has come close to the epic, haunting quality of their music.
Nirvana's "legend" only happened because they found a niche with depressive songs catering to a youth who had just come out of the gloss and excess of the 80s, were facing the first major war in a generation and had a lot of pent-up rage towards their government and what life means. Despite all of Kurt's hatred of commercialism and what happened to his music, I'm sure in some way the style he delivered took this into account. What's being a musician about if not to get your music heard. Otherwise I'm sure he would have given up long before they got to the stage they did.
IMO, he was not an overly good singer really and their music was generally distorted and not very clean (I know that's what made the "style" but still). If he hadn't died all that was left would be either to suck it up and sell out or keep flogging a dead horse (grunge started to wane by the mid-90s).
I reckon the best thing to come out of Nirvana was Dave Grohl and the Foo Fighters and in a way I'm kind of glad for Nirvana ending to allow that. Here was someone who's creative voice was stifled in that band and when he ran with his own stuff it was amazing. The Foo Fighters are a band that really craft solid rock songs and are one of the most energetic and best live bands I've ever seen. All I ever heard about Nirvana live was that Kurt never took it seriously, didn't really care for it and you had situations like the time where he mumbled/sang in an off-key for the whole set just to prove a point.
I mean, you're up there doing what you love, people are paying their hard-earned money to see their idols, at least give them a damn good show!
Bring on the flaming!
