I just finished reading Stepherson's Reamde and thoroughly enjoyed it. Yet another step away from the SiFi genre, mind you (in case you're exclusively reading SiFi), but if you've enjoyed Cryptonomicon then you'll be good with that, I think.
However, by the same author, you must read
The Baroque Cycle.
Going off topic a little, into the mix I offer
Amitav Gosh's The Calcutta Chromosome which is astounding and won the Arthur C Clarke award in '97
@Bossman - thank you for linking to that list.