This definitely veers towards the intellectually lightweight side of things, but I tend to like the Bond novels. I've read some of the post-Fleming ones, and some weren't bad, but the originals are certainly my preference. Fun, breezy reads.
A much more involved book is I Am Pilgrim, about a retired spy / forensic expert pressed back into service to find a terrorist. It's pretty long and detailed, but it really sucks you in and moves quickly, weaving the various storylines together.
Demented and sad, but social, right?