Why no Nirvana? What do you mean no alternative, isn't that rock? There's been tons of good bands since the 1990's it's all a matter of opinion. I don't know what you consider rock, since I guess Nirvana isn't, but some of my favorites are; Audioslave, Foo fighters, Linkin Park, A perfect Circle, Shinedown, Weezer. I don't really know what you're looking for here?
Well stupid Canadian, Pearl Jam and Nirvana are both American bands from the city of Seattle which is in Washington state. I think the best rock of the 1990's through the current times were grunge bands like- Pearl Jam, Alice In Chains, Temple of the Dog, Nirvana.