I've had the honor of briefly meeting Pratchett a couple of times. He was, as you'd expect, very friendly and quite witty. I hope his USENET postings are preserved.
Unsurprisingly, he got better as he got more political (public figures make better targets than fantasy tropes), and I've loaned out Small Gods, The Truth, Going Postal and others often, and they've been greatly appreciated.
I'm going to miss him.