The album version is definitely in C Major on the album. Van plays it in B Major live. It's not that hard to figure out what key each version is in, b/c I'm a musician myself; I have an ear [sometimes a weird obsession] for what key certain songs are in.
For the Chord Illiterate, Here's a list of what key most of Van's songs are in:
A Major/F# Minor- Best Behavior [around D chord], Pretty Baby [ends in Bb], Wishin' And Hopin', Annie [around D chord], Red Ditty, or Sway
Bb Major/G Minor- Private Radio and Wanted
B Major and G#/Ab Minor- ATM, White Houses [live version], All Is Well, and Rinse
C Major/A Minor- White Houses [album version], San Francisco [F in the bridge], Ordinary Day, Don't Let The Sun Go Down On Me, Devil Dance, Afterglow, All I Ask, Paint It Black, Twilight [ends in D Major/B Minor], and Paradise
D Major/B Minor- Superhero, Where The Streets Have No Name, Swindler, Prince, Sway, and C'est La Vie
Eb Major/C Minor- This Time, The One, The Wreckage, and PYHOM
E Major/C# Minor- Who's To Say [around A chord], Everybody's Got To Learn, Ameriteen [B Minor in middle], Unsung [ends with E Minor], and HAWBTW
Gb Major/Eb Minor- Papa and Morning Sting
G Major/E Minor- Time Is On My Side, She Floats, and Birdie
Correct me if I'm wrong about any of these [which I'm pretty sure I ain't].
Elicia