Well Kerry King is my answer (guitarist for Slayer), I love his speed and intricate soloing style. He is whole reason I started playing guitar, I have always wanted to learn how to play like he does.

I know I will have many purists go after me by saying: For me the best guitarist is Darrell "Dimebag" Abbott (RIP).
He combines perfectly the expressive old school style with the heavy supersonic speed modern style and represents the interface between old and new.
Hendrix is innovative and inspiring, B.B. King is classic, but "Dimebag" blows my mind.

It's really a tie between Carlos Santana and Stevie Rayvaughn.  Both of them are radical and gnarly, kidding. But in all seriousness they are two absolutely amazing guitarists that I listen to.

I have graced the guitar for may years and I can honestly say the best guitarists on planet earth are on youtube playing away and enjoying their craft while the rest of you are trying to figure out a way to measure them. It would take me a month of practice to emulate the many names that have been stated. My father only needs 48 hours to do the same. (We work for a living. Sue us.)
I do not have a responce to this any more. I had many names like Hemmet or Slash, or Santana or Clapton or Hindrix or B.B. King in my youth.
Now???
I do not have a defining name to make a reference to.
The Best is out there. I have yet to find him.
But be certain that when I do I will answer this thread.
Till then ???
Spend a weak end in any of the posters of this threads "House".
With their axe and amp or Stereo and Speaker set.
I dare the lot of you to attempt that feat and dare to make a call on this question.
I can not find the best of the best any more.
Good Luck To All.
I'm Done. Stick A Fork In Me.
Peace.

I didn't read the entire thread, but I would have to say that you all chose great guitarists.

My own personal favourite and the one who speaks most to me would be John Frusciante from the chili peppers.

There are many, many great guitarists... both dead and alive. I could spout off names, but many of them have been said in this thread already. I did notice that no one has mentioned a young Canadian gentleman by the name of Ewan Dobson. If you have not heard him before, take some time out to do so. He's an amazingly talented guy!

Of course everyone says Jimi Hendrix, Jimmy Page, Eric Clapton, but two of my personal favorites would be Stevie Ray Vaughn, great blues guy that jammed out a lot of Hendrix tunes during his career, and George Harrison as I am a huge Beatles fan I have always loved the songs like here comes the sun and while my guitar gently weeps.  A few more would be John Frusciante from rhcp, Frank Zappa yea he is weird but he is good, Duane Allman tho his career was short he was one of the best slide players, and BB King who is a legend even among blues players.

ace3llard : No way! I was reading this list thinking: "Naturally the "safe" choice is Hendrix, Paige, and Clapton. They are defninitally the most recognized guitarist... but do YOU really find them the BEST; my personal favorite is Stevie Ray Vaughan'. And then I read your post... the ONLY guy to mention Vaughan.

See everyone goes for the biggest names, cause that is what they are told. But "best" is very much the ear of the listener. It doesn't only mean "fastest" (the best rock guitarist have nothing on some flamenco and metal players' speed), it doesn't only mean creativity, it doesn't only mean they're influential; but it's a combination of all those things + personal taste.

Yes, Hendrix is "recognized" as the best rock guitarist, but who are your bests?

As I said, one of my favorites is Stevie Ray Vaughan.

Light Knight : glad to see someone else out there agrees with me, Vaughan was one of the greats I loved his music and he had a huge impact on the type of music I play and listen to. 

Jani Liimatainen from Cain's Offering, previously from Sonata Arctica.