My personal choices:
British Invasion: Dave Clark 5, Hollies.
US 1960s: Byrds, Flying Burrito Brothers, Doors, CCR; Beach Boys pre-1970.
US 1970s: Eagles, Allman Brothers, E Street Band.
US 1980s: Los Lobos, BoDeans, Bob Seeger.
Country: Delbert McClinton, Emmylou Harris, Rodney Crowell.
Britain post-invasion: Pretenders, Police, Rockpile, Elton John (yes, he had a band).
Canadian: Guess Who.
Favorite obscure band: The Brandos (Gettysburg), Aztec Two Step.
Solo: Gram Parsons, John Prine, Steve Forbert, Billy Joel, Jackson Browne, Gordon Lightfoot, Bonnie Raitt (Green Light and before).
Band that makes me think of UR: Doobie Brothers. Every band at every frat/Greek Theater/end of rush block party/Millhiser/auxiliary gym party played "China Grove," "Listen to the Music," "Eyes of Silver" or "Long Train Runnin" at least once.
Haven't really bought any current music in the last 20-30 years. Hip-hop? Forget about it.