Forge of God - Greg Bear
Also Darwins radio and to a lesser degree darwins children, though not strictly scifi.
The John Ringo books are all excellent...I especially liked 'Watch on the Rhine' "Anna, am I a member of this crew?" Hell, I think someone ought to make and sell the nuke pin.
You guys that liked the berserker stuff need to try Saberhagens other series. I actually found him via the 'Dracula' series, Dracula tape, Thorn (which ruined lost boys for me), a matter of taste, etc.
Also check out 'Empire of the east', not specifically sci-fi, but a wonderful story.
A really old book I liked was 'Nova' be Samuel Delaney.
The Dune stuff is excellent, Herberts habit of quoting from non-existant texts as if they are real is amazing and adds great depth to his vision. (the blind prophet neo from matrix was stolen directly from Dune Messiah, IMHO).
One of the best sci-fi books I have is a compilation of short stories called 'The ascent of wonder: the evolution of hard SF". I have it in hardback and it has wear points from where I hold it I have read it so many times.