David Crosby, who died at 81 on January 20, wrote only a handful of widely known songs, but the witty and ever opinionated Crosby was on the front lines of the cultural revolution of the ’60s and ’70s — whether triumphing with Stephen Stills, Graham Nash and Neil Young on stage at Woodstock, testifying on behalf of a hirsute generation in his anthem 'Almost Cut My Hair' or mourning the assassination of Robert Kennedy in 'Long Time Gone.'