I would like to meet, in no particular order...
Stephen King
Clive Barker
Christopher Nolan
John Carpenter
Monica Bellucci
Three people that I would have put on there i've already met. George Romero, Rob Zombie and Bruce Campbell.
Rob Zombie i've met twice and he was laid back and pretty cool. Both times I got a picture with him. First one(Ozzfest, signing CD's and whatnot) was just us standing next to each other not doing much but the second time I met him we both gave the finger to the camera.
Bruce Campbell was awesome. I felt bad because I had him sign a number of things but he didn't care at all. I had him sign his book "If Chins Could Kill, a photo from Evil Dead for me, a photo for one of my sisters and a photo from Army of Darkness for my brother in law. The copy of his book was a hardback 1st edition. First thing he wrote in it was "1st edition WOOHOO!!"
George Romero was really nice. He signed my DVD copy of his most recent film at the time, Bruiser. I got a picture of him, i'm about 5' 8" and he was towering over me, the guy is about 6' 5".
Other notable mentions, i've also met Tony Todd(Candyman), Sid Haig(House of 1000 Corpses, Spider Baby), Bill Moseley(Devil's Rejects, Texas Chainsaw 2), Matthew McGrory(House of 1000, Big Fish, got to meet him shortly before he died sadly), David Naughton(American Werewolf in London), Gunnar Hansen(original Leatherface), Scott H Reiniger and Ken Foree(originial Dawn of the Dead). I also walked by Danielle Harris(Halloween movies) signing people's posters and whatnot, line was incredibly long(go figure)so I didn't bother.