I like Smash Mouth a lot, but that's probably the only group that's come out in the last 15 years that I listen to.
Elvis, Linda Ronstadt, Jerry Jeff, Jackson Browne, New Riders of the Purple Sage, Emmy Lou Harris, the Pointer Sisters, the Dirt Band, CCR, Jerry Lee Lewis, Al Hirt, Chuck Berry and (only when Don Rich was doing the fiddle and guitar) Buck Owens.
My all time favorite songs, Hot Rod Lincoln, Emmy Lou Harris version of Pancho and Lefty, LA Freeway (Jerry Jeff), Fairy Tale (Pointer Sisters), Panama Red, Take it Easy, Chantilly Lace, Lookin Out My Back Door, Jailhouse Rock, and (doggone it, alzheimer's moment) what's the song Tommy Lee Jones puts on the 8-track when they're driving upside down in MIB?
All time worst song ever recorded, "It's a Sunshine Day" by the Brady Bunch, possibly tied with Sugar, Sugar and anything by Tony Orlando and Dawn.