Just my 2 cents on the matter, I feel both are highly subjective. In regards to the most influential guitarist, how could you not pause to make exception for the guy who invented guitar? Likewise, the founders and pioneers of each genre that has formed since? There's no question that the 80's were the years of guitar heros, giving birth to techniques far beyond anything anyone had ever envisioned. Guys like EVH have completely lost everything that made them what they were. His composition and technique are down the drain, but that doesn't detract at all from the mark he left when he hit the scene and blew everyone's mind!
I mean, you have the Jimmy Page's, the Jimi Hendrix's, the Yngwie Malmsteen's, the Django Reinhardt's, the B.B. King's, the Albert Lee's, the Andres Segovia's, and so on and so forth. Because of this, there is absolutely no way in my mind that you can quantify even a handful of, "most influential" or, "best" guitarists! Not by a long shot. Now, everyone has their favorite guitarist(s) and I'm all for that, but the ability to influence or to be considered, "the most influential" is only as good as the reach an artist has. I think this is even more important to recognize NOW than it's ever been!
With the birth of the internet and the ability to put yourself out there, "the best" is only as notable as the musicians you've been exposed to at any given point in time. I am constantly under the impression that I've just about seen it all in regards to everything from the most astonishing technique to the most beautifully crafted compositions. Then, I hop on YouTube or surf around on MySpace and there's some nobody sitting in his bedroom who bests even some of the most current influential big named musicians! I can't help but take that into consideration in regards to the past and who might've been considered absolutely groundbreaking but they just never had the contacts or abilities to make a name for themselves.
Take, for instance, Shawn Lane in 1978 when he joined the southern rock band, Black Oak Arkansas at the ripe old age of 14. If you hop on YouTube and pull up some old footage of Shawn doing his solos with that band when he was 16 and 17 (thus putting the year at 1980 and 1981), right there is a kid who is already absolutely pioneering his own voice on the instrument. I mean... if you had put him and EVH in a room together in 1980, you would've easily had a jaw-dropping performance from two completely different guitarists leveraging their very own techniques not used by anyone before them (that we know of) in the capacity they were. Granted, those days were arguably the pinnacle of Eddie's writing and technique, but Shawn was FAR from done and his reach wouldn't truly start until he hit his early 20's during the burst of flashy guitar technique being the holy grail of the measure of a guitarist. Even still, his following was (and still unfortunately is) somewhat underground, but there he's been since 1979; a musician with the capacity to move mountains with technique who would become an INCREDIBLE composer and force to be reckoned with. And that's just Shawn Lane!
Anyway, I'm a 27 year old guy who has been playing for something like 11 years. My first influence was Kirk Hammett. From there, it was Marty Friedman, Dimebag Darrell, Yngwie Malmsteen, and the list grows every day, it seems. While I appreciate where they were in their time and the effects they had on MANY people, guys like Hendrix just don't do it for me. I appreciate and acknowledge where they stand in the line of influences, but just because, say, Nuno Bettencourt is influential to me doesn't automatically make Hendrix an influence of mine due to Hendrix being an influence of HIS, you know what I'm sayin'?
But yeah. That's how I see it. The people who influence you had people who influenced them and so on and so forth. I'm all for making a massive list of influential guitarists and someone actually putting forth a STUDY (not just asking people their opinion) in attempt to quantify the true reach of any given guitarist - actually, I think that would be quite interesting - but none-the-less, there's my opinion of the matter... for what it's worth. lol.
-Stephen