Wow, came across you by chance, and our tastes are extremely similar -- "good music" of all sorts, played by people who know what they're doing! Particularly nice to find another Cosmosquad / Blotted Science listener.
You're right; petrucci is the karate kid of guitar. Tony Levin is the diverse sagely musical master. petrucci has the technique, the knowledge and the feel, but not nearly the diversity that Levin demonstrates.