I'm not a Rufus Wainwright fan because I didn't know too much about him (only about his father, whose music used to amuse me, and who once got propositioned by Brian Epstein while on tour) ... until the discussion of his what I hear is an icky version of "Across The Universe" for the Canon camera ad (which I haven't heard yet). But Rufus also sang "Hallelujah" (<- this is a probably illegal link) for the Shrek movie ... and his voice is emotional, mostly clear and on-key, and his vibrato very sweet.
Rufus is the son of the (mainly) humorous singer, Loudon Wainwright III, who was part of the "New Bob Dylan" scene in the late 60s & early 70s (and subject of a humorous ode to Dylan on the singer's 50th birthday). Loudon is best known for his song "Dead Skunk in the Middle of the Road."
Looking at some photos of Rufus now, I discover that, OMG, he's one sexy-looking gay guy! Whew.