It's a day that tabloids have been counting down to for months now—Jennifer Aniston turns 40 today. Others celebrating: Sarah Palin is 45. Jeb Bush is 56. Sheryl Crow is 47. Brandy is turning 30. Kelly Rowland is celebrating her 28th. Carey Lowell, the actress and wife of Richard Gere, is turning 48. BMG chief exec Barry Weiss is 50. IAC's Michael Jackson is 51. Interior designer Kitty Hawks is 63. British fashion designer Mary Quant is 75. Aubrey O'Day is celebrating her 25th. And Burt Reynolds is 73.