Also called Post-Grunge, Alternative Rock was a style that record labels and media embraced after the short lived but dominant Grunge movement by the Seattle four (Nirvana, Soundgarden, Alice in Chains, Mother Love Bone/Pearl Jam). The very early and very heavily umfluenced are the only I would call post-grunge, such as: Stone Temple Pilots, Bush, Candlebox. Alternative Rock has become the most played music on modern rock stations and has in the last about 20 years has essentially with few exeptions has taken over the world of rock as it was once known. Like it or not it's all over the radio, and all over the stores.
(Rest in Peace: Layne Staley, Kurt Cobain, Mike Starr, and Andrew Wood. You were truly the inspiration of a generation along with: Jerry Cantrell, Chris Cornell, Eddie Vetter, and David Grohl who are still rocking.)
There are to many Alternative Rock bands to list but a few include: The Smashing Pumpkins, Foo Fighters, Staind, Queens of the Stone Age.