At 32 Waldner won the World Championship for a second time (1997), at 35 he got the silver at the Olympics (2000) at 39 he got to the semifinals at the Olympics (2004). Pretty impressive stuff. I think Wang Liqin is pretty amazing too. But someone said he is 35, according to Wikipedia his birthdate would make him 33 as of now.
But I want to know where all the bad boys of Table Tennis are. In the 1970's John McEnroe had a reputation for throwing tantrums and yelling at the refs. Jimmy Connors did a lot of that stuff too, and then there was Ilie Nastase, and his nickname was Nasty. He earned that nickname. How come Table Tennis does not have anyone like that. I would say Zhang Jike is probably the closest but it is not out and out disrespectful. I have to say, when I see that stuff I am entertained.
I also like the confident cockiness of Ricky Henderson when he was at his peak. In baseball he would often lead off a game by walking, take this huge, outrageous lead taunting the pitcher, steal second when the pitcher tried to throw to first on a pick off move, totally disrespecting the pitcher, and then steal third on the first pitch after he got to second. And all of a sudden you had a pitcher who had not even given up a hit yet, totally rattled and a man on third with no outs. I also liked how Muhammad Ali would get inside his opponents head by saying ridiculous things that were very funny but made his opponent angry. When he fought George Forman he kept grabbing Forman by the back of the head and yelling in his ear, "you hit like a sissy, how come everybody told me you hit hard?"
Now Zhang Jike is cocky and a little aggressive, but he is in great shape. It is hard to argue with Wang Liqin and J. O. Waldner. Their records speak for themselves. But, I will also go with Zhang Jike because he is in great shape (a lot of his power comes from how strong his legs are), he has won the World Championship in his first attempt, I think we will be hearing about him for years to come, and in interviews he has said stuff to indicate how great he thinks he is.
Ma Long is pretty solid as well. I love how much bigger Ma Long's right arm is than his left.

Too bad Ma Long is so polite.