I didn't know him, but met him once. "This is the guy from Ithaca!" he told the woman he was with at the time--Wallace was born here in 1962. I found him to be cheerful, funny, and very collegial to a writer he didn't have to give the time of day to.
This blog offers its condolences to his friends and family, and everyone who liked his stuff, as we did.
EDIT: After sleeping on it, I am feeling even more devastated about this. I'm not sure how many other writers feel this way, but it's as though our generation has lost its literary leader--Wallace's writing was never universally praised and loved, but his status as an innovator was unchallenged, and I think he served as an example to a lot of us. He was the first writer our age who got out there and distinguished himself--a guy about whom you could think, at least somebody is trying that kind of thing. He was our Barthleme, or Borges, and I suspect that a lot of people who don't like him now will admit ten years from now how great a writer we just lost.
Rhian pointed out something to me last night that I don't think is often said about Wallace: he cared very, very deeply about his subjects, and took everything to heart. This was manifested most powerfully in his essays--his piece about the Iowa State Fair, for instance, and the more recent "Consider The Lobster." It's easy to speculate that perhaps it was this powerful, painful engagement with the world that killed him.
I dunno. I've always considered myself to be a fairly self-contained writer, but today I feel rudderless.
ANOTHER EDIT: Oh, for Pete's sake:
Two later collections of stories — “Brief Interviews With Hideous Men” (1999) and “Oblivion” (2004), which both featured whiny, narcissistic characters — suggested a falling off of ambition and a claustrophobic solipsism of the sort Mr. Wallace himself once decried.
That's our Michiko, couldn't resist one last swipe. FWIW, I think those books are excellent, particularly the former.