I've met quite a few bands in my time, but I'd have to say the notables are (and, guaranteed I'll leave people out that dont immediately come to mind):
In Flames-all were awesome each time-posing for pics and hamming it up for the camera-always fun to have lighthearted photos with bands!
Mike Gaspar (drums) from Moonspell was fucking cool as hell. We blabbed about lots of things, and he stuck around for quite some time and was very cordial. Was impressed with my Moonspell long sleeve too-he hadnt seen one person in America (till that point I s'pose) with it-had the old logo and everything.
David Vincent and all of Morbid Angel (didnt meet Trey though) circa '95. Hung out and shot the shit at the tourbus for about an hour and a half. Vincent's a real nice guy!
Pantera were badfuckingass. Real down to earth dudes, and signed everthing put in front of them. Their crew is fucking off the wall funny too. Whoa, Val!!
Zakk Wylde, aka
The Man. Signed my buddy's trenchcoat with "Eddie Vedder is a cunt". Classic. Nuff said.
Mitch from Napalm Death. Hung out for about an hour, just bullshitting about music, and had some killer Kind Buds to share!! Always a treat!!
Speaking of smokin good buds with bandmembers-add Bonz from Stuck Mojo, Gene Hoglan, King's X's Roadie (who let me in as crew to see the Gathering before I was 21!!), and MCUD from Hedpe (ran into him at Ozzfest wandering around aimlessly-I said hi, and he gives me a joint to share. Good deal if you ask me).
Tompa Lindberg (ATG-era)-Funniest drunk motherfucker I've ever seen. Was absolutely destroyed when I met him. So funny. He walks into the middle of the parking lot, facing traffic, and pulls out the willy to piss. Gotta respect a guy who just doesnt give a fuck. I think.
All of Biohazard were cool as fucking hell. Tough lookin' dudes, lemme tell ya. It was nice they didnt act all Brooklyn or whatever.
And a million more...but these are the first to come to mind.