I'm glad this poll came up. It forced me to sift through what's left of my memory and try to remember guitarists I've met.
The most nebulous was someone who bumped into me right before the start of a Ron Wood/Bo Diddley gig. ""Pardon me," said a very British voice. Yes, it wasn't Bo Diddley.
The briefest were handshakes with SRV and once when Chuck Berry told me he was too busy for a handshake in the midst of signing autographs.
Which may sound toolish, but in 1983 (!) I saw Alcatrazz open for Ted Nugent, and Yngwie came out to watch Ted. When he shook my hand, he literally tilted his head back, the better to look down his nose at me. Tool Crown goes to Yngwie.
Briefly met or got autographs/photos with Rudolf Schenker, Mathias Jabs, George Lynch, Dave Mustaine and Marty Friedman.
I met Brian Robertson (and Philthy Animal Taylor) when they were playing with Frankie Miller in 1987, opening for Bob Seger.
That same year I met Brad Whitford at a Gary Moore show.
I met and spoke at length with Vernon Reid, who I remember quoting Sting as saying that being on tour was like Field Trip of the Damned. Vernon was REALLY a nice guy, and we actually talked very little about music.
I also met the last surviving roadie from the Allmans Fillmore back cover photo, though I imagine by now he's passed.
Working for Warner Hodges and thus spending considerable time in Nash Vegas, I've met a LOT of guitarists, including Dan Baird, Audley Freed, Jeff Cease, Rick Richards, Sonny Landreth and bassist Michael Rhodes. Others too, but those are the ones I can recall.
All of them are really nice people, and that's the beauty of Nashville; no one's got an attitude because everyone is someone.
I met Joe Bonamassa when he and Warner played on the same bill in Nebraska. Not a fan, though his rhythm section were really funny guys and a lot of fun to talk with.
Got to go backstage for the Eat 'Em and Smile tour in 1986 and spoke at length with Steve Vai and Billy Sheehan. Steve was very tolerant of my questions, but Billy was a lot more fun.
I met him again in 2008 in Singapore at a pre-show meet-n-greet for Mr. Big. All of them, who had just gotten to SG from a run of shows in India and were obviously not enjoying the weather and exhausted, came across as very sincere in thanking me for being there, especially when I told them I'd come from Hong Kong just for the show.
The show was outdoors (you can watch all of it on YouTube if you search), and I could see that these guys were suffering. But after the show, Eric Martin came out to sign autographs and take pictures. And he looked like a heat casualty.
It's hot and humid in Singapore and we had to wait outside for the photo shoot, which is why I'm sweating like a hooker in church in that photo.