It's conceivable that the double-disc Decade—a staple of dorm rooms and used bins everywhere—fits most people's needs for a Neil Young hits collection, and perhaps that's why the sonic stickler has chosen to leave well enough alone since its 1977 release. But now there's Greatest Hits, a single-disc collection whose fidelity has been pored over, even while its not-quite-one-sentence explanation ("Greatest hits inclusion based on original record sales, airplay, and known download history. —N.Y.") was not. Leaning heavily toward Young's late-'60s and early-'70s heyday, it features every expected, rightfully canonized song, from rockers with Crazy Horse ("Down By The River") to his more subdued classics ("The Needle And The Damage Done," "Heart Of Gold"). "Cortez The Killer" and "Walk On" are missing, but they wouldn't replace any less-worthy tracks if they were here.