I played lots of air guitar in the 80's listening to Maiden, Priest, Scorpions, AC/DC etc etc. And we will not even talk about the beer that was consumed while doing this. But since I picked up a real guitar 4 years ago and started playing these 3 are the ones that are inspiring me right now.

Paul Gilbert - Not his old stuff. Mainly his last 2 albums. Get out of my Yard and his new one just released. Silence followed by a Deafening Roar.

Vinnie Moore
Gary Hoey

Honorable Mention to:
Joe Stump - He is accused of being a Malmsteen clone and this may be true but I like his stuff better.

Blues Saraceno
John Petrucci - Was suprised that his name did not really come up on this thread unless I missed it somewhere.
John 5 - The guy plays country licks in Metal songs! He has developed his own style for sure.