On his 1991 release Girlfriend, Matthew Sweet basically trademarked the concept of Weirdo Power Pop. Drawing on contributions from downtown legends (Fred Maher, Richard Lloyd, Robert Quine), a first-call slide player (Greg Leisz), and even Lloyd Cole, Sweet starts the program with the grimy “Divine Intervention,” a song that juxtaposes sunny harmonies with decidedly after-midnight guitars and lyrics of existential heaviosity (and a false ending). And then, then, he segues into the shimmering jangle-pop of “I’ve Been Waiting,” which is perhaps the most perfect love song in pop music history. Girlfriend is timeless in the literal sense: someone who wasn’t already familiar with it would probably have a hard time guessing what decade it was made. And that’s a good thing.