Sphere was good. The Lost World also wasn't bad, as sequels go. I don't think I ever read Timeline. I guess I should.
I also read Airframe but I don't remember all that much about it other than that there was a lot of swearing.
Don't think I've read anything else of his other than the six I mentioned, but I can't remember for sure.
The news about Crichton dying probably got swallowed up in the election, because as I recall it happened right around the same time.