Following my formula from the 2007 2008 and the 2009 2010 threads
2003 On the WWE Title side, we had Kurt Angle and Brock Lesnar holding my favorite WWE Championship Title Belt design ever, while on the World Title side, we had Triple H and Goldberg holding the Big Gold Belt.
2006 On the WWE Title side, we had John Cena, Edge, and Rob Van Dam holding the Spinner Belt, while on the World Title side, we had Batista, Kurt Angle, Rey Mysterio, and King Booker holding the Big Gold Belt. On the ECW Title side, we had Rob Van Dam, The Big Show, and Bobby Lashley holding the Bloody Barb Wire Belt.
From the Main Event scene alone, I think 2003 takes it, but thats just one of my personal favorite years because of WM XIX. ECW did help 2006, but not enough for me to pick over 03.