For me it was Jeff Kinney. I was meeting a different author I love, but there wasn't enough room downstairs and we had to go up. Turns out that's exactly where Jeff Kinney works! He's the author who got me into reading so I thought that was so cool
Brian Blessed is probably the most known person I've met. He is exactly like his appearance on any TV show you've seen him on. He wants to tell stories, endlessly. He's always got a fascinating story or fact to tell you. He wants to speak to literally anyone about anything.
This was at a convention years ago, and he had two handlers who were ripping their hair out from the frustration - they were bitching about how impossible he is to get from place to place but he's just so goddamn nice.
Other notable meet (to me) was Regi Fils-Aimé. I was wearing a Zelda necklace and he went "ooooh I like your necklace!" and I pretty much resembled that scene where Troy meets LeVar Burton in Community.