Nirvana really saved my ass when I was a teenager. In the small town where I come from you had no chance to find cool music, and when I got fed up with metal, the only thing I could get my fingers on was crappy pop music like (yuck!) The Police. Then came grunge with Nirvana and Pearl Jam, and even though I settled for Mudhoney (the only grunge band I still really love and listen to), Nirvana were the first cool guitar band I saw on TV. Because of the hype TV stations broadcasted more guitar music (e.g. Pavement, and even the mighty Melvins), so suddenly there was loads of music to discover from that point on, even in a town where the next cool record store is an hour away by car.
I really like Nevermind, even though I can't listen to it anymore. But I'd definitely say it's a pop record, not a rock record. But what's wrong with pop if it saves a bored and desperate teenager?
And I don't think Cobain got killed. I think he was on drugs and painkillers, had depressions and the wrong friends. Maybe his suicide was a bit too much attitude, but when I heard about it I was sad nevertheless. Poor bastard.