I spent all last week on a testing range in Alabama. No internet. I considered myself lucky to have indoor plumbing. I spent a large part of the time huddled into a shady equipment shed reading paperbacks to avoid the burning gaze of the Daystar. The verdict?
Charles Stross's Atrocity Archives is good read. I didn't buy the whole IT support by day, field operative by night approach to the book. Nobody would organize their organization that way unless they were ridiculously understaffed. The book explicitly states that the Laundry is in fact ridiculously overstaffed because many of the employees are too dangerous to be employed in mundane society. But it made for a fun contrast anyway. It also handled magic in a much better way than the language hacking of, say, Snow Crash.
John Scalzi's Ghost Brigades is as good as Old Man's War. The plot is good, characterization is solid, and things move well. It gets into some of the moral concerns touched on in Old Man's War like the Colonial Union keeping Earth in the interstellar dark ages.
Isaac Asimov's Foundation is a bit dated though and his technology tree and timeline don't work. You're not going to have a non-nuclear star-faring society. What are they going to run their starships on? Coal? He also seems to base a large part of his ideas on the fall of the Roman Empire, but the reason a lot of technologies disappeared with the fall of Rome is not because people forgot the technology (at least not at first). The reason they regressed is because they could no longer afford to pursue or maintain certain technologies with the economic collapse of the empire. You don't discard plate armor for maille because you forgot how to make plate. Making plate is easy if you have the metal. You discard it because metal is hard to come by and the labor is cheap. Actually losing technologies requires generations of economic decline not singular generations.