Rarities: 1971-2003 (2005)

Imagine what would constitute a set of Rolling Stones gems from the vaults (the title theme to C -- -sucker Blues, say). Okay, keep imagining. Nearly half of Rarities: 1971-2003 consists of readily available tracks, such as live remakes from recent concert discs; the rest — B sides and remixes of forgettable later hits like ''Mixed Emotions'' — are trivialities. A strutting 1971 take on Chuck Berry's ''Let It Rock,'' which truly is rare and worth unearthing, hints at what this mistitled hodgepodge could've been — but isn't.