Mathis Landwehr - The Next Generation
I would like to say that I agree with take-sensei on his list, and what Dragonking said about the old Masters.
A friend of mine, Lightening Bear, who is a stuntman and worked on Billy Jack, and also trained with Bruce Lee in the 1960s, told me that for a small man, Bruce Lee, had such power in his fighting technique, it was explosive. One day he was training with Bruce, and was knocked clear across the room. Lightening Bear is about 6'2"!!!
I recently met and became friends with a martial artist in Germany called Mathis Landwehr, and he is a person to watch. Have a look on his youtube page and judge for yourself. He recently released a movie in Germany called Kampfansage, sequel out soon. He is an extremely dedicated and hardworking martial artist, and I am proud to be his friend.
http://www.youtube.com/watch?v=2p-Djp4_6aU
As for the older martial artists, including Chuck Norris - these people have had their day and with regard to David Carradine, he trained as a dancer! The same goes for Jean Claude Van-Damme, who studied ballet.
Steven Seagal is obviously older now, and a bit slower, but still a great martial artist.
Yours in the Dharma,
zenswim