You haven't lived until you've heard Matthew Rodgers sing ''(Sittin' on) the Dock of the Bay.'' And then you may just want to die. American Idol Season 3: Greatest Soul Classics is a cash-in collection of all 12 ''American Idol'' finalists struggling through painful, emotion-free renditions of old soul hits. Even the best crooners of the club (hello, La Toya London!) are sabotaged, thanks to generic, passionless backup arrangements. Throw a little Leah Labelle on top of it, and you're truly in a world of hurt.