To be honest, Waldner's variation just isn't possible in today's game. The speed and more importantly the amount of spin in today's game makes it so that the margin of error is simply too small to do all the varied things that Waldner did to any consistent degree.
I don't know I would say if Ma Long's forehand is the best, simply because he pushes the speed so much and relies predominately on speed, that because humans can only react so fast, he sometimes causes himself to mess up or ends up giving himself too little reaction time, when someone just back his hit or adds just a little bit to the return shot. Its why his win percentage against Boll isn't as good as good as it should be. Boll is good enough with offense and is consistent enough to get it back often that Ma Long sometimes is caught not being able to adjust quick enough for the next shot.
Don't give me wrong though, most players aren't good enough to take advantage of this, and he has practiced enough, and is so quick that usually this isn't a weakness, and he is able to adjust quick enough.
Spin and speed are actually less than the 38 mm days. The difference today is that countering is harder with the heavier ball. The 38 mm was somewhere between 15 and 20 percent lighter than the 40 mm ball and in today's standards it's only gotten heavier. And who knows what it will be with the new pvc ball coming out after 2012.
I hate when people compare Waldner to today's game. He in his prime wouldn't be able to do what he did during the 38 mm ball era. Service, point system, technique, and tactics are all different from his era to ours. Not to mention that he evolved the game and the Chinese have taken what he did to the sport and evolved it again with Wang Liqin, Ma Lin in the Early 2000's, and Ma Long and Zhang Jike in the later 2000's.
Ma Long's forehand is quite fast, but it also has more spin than any non Chinese forehand. He's pushing the trinity not just the speed of the shot. Boll played so well against Ma that he could attack Ma's Backhand (where he would step around) and then block to the open forehand. It's why Ma started to work more on his Backhand to make it more consistent and more powerful.
Ma in his earlier years was too focused on using his forehand as much as possible rather than pay attention to his tactics. It's why he did so great last year, and why when he recovers from his injuries fully (which could be very soon from how's done lately) he'll climb back to number 1 again.
@ Carl - Wang Liqin to this day still has the strongest forehand. If you watch their matches Wang and Ma are very close in style in that Ma rarely drop shots someone who's lobbing and chooses to over power by slam as WLQ did. When WLQ can instigate his forehand he has a higher winning percentage of that point than anyone on the Chinese team. Because he's lost a lot of his speed in footwork they force errors to his backhand because he knows if he steps around they'll put it towards his forehand and he'll miss the counter. Ma is perhaps the only player that will let WLQ play a forehand to forehand rally, but wins typically only by shooting one down the line towards his backhand making WLQ hit a defensive lob or a poor counter.
@ DaKrazed - um the left hand is typically an aiming point of origin. It helps to show where the ball will likely go because it's approximately where the paddle will be at the point of impact. And the physics of it would only apply torque if he were actually able to grab onto something which in the case of TT is the table and illegal. Force is equally pushed and pulled upon two opposing objects so to apply torque Ma would need something else to touch in order for him to increase his torque. Just wanted to be clear there.