His lecture was held on the the topic "In Defense of Fantasy", which was a wide-ranging discussion of the always prickly relationship between fantastic fiction (broadly defined) and mainstream "psychological realism". Not a bad talk, but especially wonderful was his use of quotations to organize it.
And, yes, I'm a big enough fan to ask for a couple autographs for "Iron Council" and "Perdido Street Station". Turns out he signed his books with very apt quotations from Blake and Burns. It sounds a little pretentious, but he's really not a pretentious fellow, just very earnest and passionate about a wide range of literature. You should have heard him go off on Gulliver's Travels, early negative reviews of Tolkien (Oo, Those Awful Orcs!) in the mainstream press, and so on. I'll go into more detail later, behind a cut.