Vernor Vinge is another great hard sci-fi author. "A Fire Upon the Deep" is a space opera epic if I've ever read one. Currently finishing up "Rainbows End", and wasn't sucked totally in until maybe 1/3 through, but now I'm hooked :)
Rainbow's End is one of my favorite books. I have probably read it 4 or 5 times since 2007. I find the ideas in it have gotten more accurate as time goes on.
