If 20 years sounds like an inflated tenure for the romantic-gloomy Liverpudlians, well, it is. In additon to the band's '80s heyday, ''Crystal'' takes into account frontman Ian McCulloch's five-year solo foray, his brief stint (with Bunnymen guitarist Will Sergeant) in Electrafixion, and the Bunnymen's recent comeback incarnation. That said, this bountiful four-CD anthology includes some of the most inspired covers (the Stones' ''Paint It, Black'' and the Modern Lovers' ''She Cracked'') that peppered -- and sometimes comprised -- their live sets. Those are in addition to the highlights of their uneven catalog, and alternate versions of faves like ''The Killing Moon'' and ''The Cutter.''

