It's been a while since I read Science Fiction (on a fantasy kick now-a-days), but I love Sean William's Evergence Trilogy
and ...of the Earth
trilogy. And of course, there's my favorite book ever, The Hitchhiker's Trilogy.
If you ever get a hankering for fantasy, I highly recommend Butcher's Dresden and Codex Alera series.
Oh, and of course, anything by Michael Crichton.