Far and away Nirvana. They're credited with so much innovation, but they basically just combined the sounds of The Replacements & Husker Du and mainstreamed what'd been going on on the alternative seen for the prior ten years.
They weren't even as instrumental in launching grunge as were Pearl Jam and Soundgarden.
In Utero, their third album, was initially so bad that the band were basically forced by Geffen to remix it.
I mean, Kurt wasn't even the most talented member of the band.
Definately over rated. If Cobain hadn't died, I'm sure they would've faded away by their fourth album.