Interesting: Despite having a lower Gooodreads rating than Pattern Recognition, I liked Zero History far better. Maybe Gibson's style finally grew on me, but I don't think it's just that. There's a bit more depth here, less empty hype (to me, at least).
I skipped Spook Country (Blue Ant #2) for the simple reason I didn't have it -- I got Pattern Recognition and Zero History not knowing they were a part of a trilogy. Zero History worked fine even without knowing what happened in Spook Country, even though many of the characters carried through from the previous book. Now I'm not sure whether or not I should read Spook Country.
A good read.