All-time favorite: "White Lies, Blue Eyes" by Bullet, available on Rhino Records' HITS OF THE 70'S: HAVE A NICE DAY cd series.
All-time worst: "I've Never Been to Me" by Charlene (incredibly, on Motown Records), although at least it's so bad that it's funny. The very worst song I have ever heard is by a slightly more than 1-hitter, David Lee Roth of Van Halen, with this thing he recorded in the 1980's called "Yankee Rose," which sounds like fingernails scratching a chalkboard.
I also recommend the excellent ONE HIT WONDERS BOOK by Wayne Jancik, although Billboard, the publisher, only let him include half (the Top 20 acts) of the essays he wanted to include.