The guy is everywhere. I know him best as Obi-Wan Kenobi and Plo Koon, but he's also brought life to characters such as Johnny Test, Green Arrow, Harry Osborn, and that's just the tip of the iceberg. He's been in video games, he's a double for many celebrity voices, he's an announcer - just check out his resume.
He recently shared an entertaining video about voice impressions. Over the course of five minutes he goes through impressions of several actors, and it's pretty amazing to watch him switch from one to the next and sound exactly like people such as Jay Baruchel and Morgan Freeman. See for yourself:
Visit JAT's website to learn more about his work and to see more videos.