She collaborates with fellow titans like Beyoncé and Tony Bennett as compellingly as she tweaks girls-night-out anthems into battle-of-the-sexes broadsides. She can strip her elaborately constructed hits down to their piano-and-vocal essence, or put a naughty spin on Christmas music. In any context, Lady Gaga's outsized personality and well-honed artistry turn the songs she touches into pop gold.