I actually got my wish. I got to meet Lois Mcmaster Bujold, author of the Vorkosigan and Chalion series. She's gracious and clever and an all-around nice person. (Plus, she writes some truly fantastic books.)
Thanks to conventions, I've had the opportunity opportunity to meet many writers whose work I've admired. Josepha Sherman, Terry McGarry, Patricia Bray, Louise Marley...every single writer I've met has been kind and helpful. It's wonderful.
I even got to say hello-very briefly!-to Terry Pratchett and Neil Gaiman at last year's Worldcon. They really are that brilliant, and very polite too.