Lady Gaga, Sting, Madonna, Bruce Springsteen, Billy Joel, Mary J. Blige, Herbie Hancock, Stevie Wonder.
Gaga of course means the most. I've met her on several occasions, but the two that stick out are being a member of the You and I MTV Premiere/Interview (got to spend an hour within feet of her

) and meeting/talking/posing for pics with her at the Terry Richardson book signing.