Sarah McLachlan: Mirrorball.

This video companion to the Canadian singer-songwriter's triumphant live album confirms in sight what that recording advanced in sound--Sarah McLachlan and her fine, flexible stage band have evolved into a superb live performing unit, breathing added fire and nuance into McLachlan songs that were already stunning in their original studio versions. Always a strong, charismatic singer, McLachlan now conjures a rare balance of delicacy and power, measured here in performances of signature songs that add a new, more muscular edge matching her band's rock firepower. Thus, "Possession" expands beyond its already sensual promise to touch on truly erotic abandon, while "Building a Mystery" focuses its portrait of a narcissistic poseur with a harder edge and a newly amended, R-rated lyric that's entirely appropriate.