I wouldn't recommend Scalzi. Much of Scalzi is miltiary scifi with little realism and isn't a great introduction for scifi. I'd recommend Charlie Stross. "The Atrocity Archives", "Singularity Sky" and "Halting State" are all excellent. The third is very weird in that it is written in the second person, but is lots of fun. Other good authors to start with are Pournelle and Niven (Ringworld, The Mote in God's Eye, and King David's Spaceship are all excellent).
Am I somehow unusual for being seriously weirded out by the cultural undertones in Scalzi's Old Man's War books? I keep seeing people in generally enlightened forums gushing over his stuff, but the book read pretty nastily to me with its mix of very juvenile approach to science, psychology and pretty much everything it took on, and its glorification of genocidal war without alternatives. It brought up too much associations to telling kids who don't know better about the utter necessity of genocidal war in simple and exiting terms in real-world history, and...
And happy new year to everyone.