Nobody's mentioned Eddie Van Halen or Alan Holdsworth yet! Both are tops in their genres.

Van Halen revolutionized rock guitar playing (followed close behind by the likes of Joe Satriani, Steve Vai, et al).

Holdsworth, with his fusion-like sound and incredible, flowing lines carved out his own niche in the avant-rock/jazz world.

A couple lesser-known jazz players that I consider significant...

Cal Collins - a straight-ahead West-coast player - amazing chops.
Herb Ellis - straight-ahead player in the Joe Pass mold. Made great recordings with Ray Brown and Oscar Peterson among countless other luminaries.

And then of course, there's Mike Stern - brought to greater prominence by Miles Davis when he made his early-eighties comeback, Stern plays an incredible mixture of bebob and rock that sounds totally unique.

So many great players it's hard to mention them all, but we've made a great start

I saw Mark Knopfler with Dire Straits in a small club in Atlanta a few months after their first album started hitting it big - what an amazing musician. And Stevie Ray Vaughan needs no introduction. "Texas Flood" remains one of my favorite albums of ANY genre