Nirvana was pretty good.  I remember back in the early 90's that if you didnt like Nirvana or Metallica, you weren't listening to anythign good, or that your opinion sucked.  I wouldn't go that far, but they are definitely a good band.

Let's not forget that Nirvana's popularity had influence outside of bad hard rock acts. It wasn't all about STP and that group that sang 'Blackhole Sun'.

A lot of good 90's american pre-existing and new alternative acts (falling into the indie rock/pop bracket, not metal) such as Dinosaur Jr, Urge Overkill, the Breeders, Sebadoh, Afghan Whigs, Beck, Superchunk, Lemonheads ,heck even Weezer, got signed to labels (or, if already on indie labels, were offered better deals with major labels looking to cash in on the next big thing) as a result of Nirvana's success becos the industry believed Nirvana were responsible for some kind of alternative explosion. Some of these groups even were quite successful...'Smashing Pumpkins', for instance.

Wow, someone stirred up a hornets nest with this question.

Grunge like New Wave in the 1980s is a decade specific music. The arrival of Grunge signaled the end of Glam Rock, though the recent Bon Jovi concert I attended in Sacramento, CA at Arco Arena was sold out meaning some of that Glam Rock survived and some acts still sell out arenas.

Glam Rock was not all that bad. People forget Guns N' Roses which was started in 1985 from the ground up did not have their hit record, Appetite for Destruction, until 1987. In this sense, Guns N' Roses was not some Motown/American Idol band where they auditioned in front of record execs and had all their stuff written for them.

If people think of Glam Rock as contrived, then what about Motown with Marvin Gaye, Stevie Wonder, Michael Jackson, Diana Ross and others? The Motown way of making music is to separate the performers from the writers and producers who make the music whom the performers use to get to rock star status. Motown in many ways is more contrived than Glam Rock ever was.

That being said, Offspring, Nirvana, Pearl Jam, Live and others had some really good music. Granted, the "My life sucks, I don't care" negativity and references to heroin use in Grunge was downright depressing. Grunge spoke to a generation at a moment in time where they could relate to it.

That time has passed.