I have been playing classical and acoustic guitars for years, and now I plan to buy my first electric guitar. I can spend about 2000€ (aprox. 2650$). I have been exploring a little bit on the web and I finally I think I'd buy either the PRS DC3 or the Music Man Silhouette Special. Unfortunately, there is no dealer with this guitars close to home, thus I cannot test them easily (though I'll try). I want the guitar to play Petrucci, Satriani, Steve Morse or even a little bit of blues or jazz, either at studio or on stage. Which one do you think would cover these styles? Furthermore, the MM can be setup either with HSS or SSS, but I think the HSS is more versatile, isn't it? Any other advises on guitars within this price range?

No experience at all with PRS, but I have a Silhouette standard (HSH) and it is a great guitar. It is versatile enough to play anything you want and has one hell of a neck.
And yes, HSS would be more versatile.

I personally couldn't see myself not recommending a MM guitar, as they are extremely well made. As for Petrucci and Steve Morse, don't they actually have signature guitars from MM?