Vernor Vinge Rainbows End.
This is the novel length follow up to the Hugo-winning "Fast Times At Fairmont High", which expands on the short Vinge had published in IEEE Spectrum a couple of years ago. I suspect that this is set to be among the best SF novels of 2006. Vinge uses his home city of San Diego as the background for a meditation on continuing education, life-long learning, and identity. A fascinating book that touches on recurring themes in many of Vinge's work. If you know about my research projects of old (which have remained continuing interests), then you'll not be surprised that I loved a book that expanded on so many of them. There's a lot in it about ubiquitous networks, reputation management, context, digital collaboration, co-presence, affinity hierarchies, and the meaning of identity in a highly networked world - one major character's identity is being spoofed three ways. And it's all wrapped up a cracking SF story.
Charles Stross The Family Trade and The Hidden Family.
Charlie takes on the alternate worlds/alternate history pack with a story that throws a business journalist into a world of feuding families, mercantile economics, and intellectual property trade. Two books that are best thought of as one in two parts. Miriam is a sparky heroine, with a unique take on the opportunities and perils of suddenly finding herself part of a family of world-walking merchant adventurers. An interesting spin on an old theme. The rest of the series will be worth watching.
Jennifer Cruisie Charlie All Night.
An early Cruisie book, this is one of her Riverside books (but set in another town). A radio producer finds herself with an annoying new presenter to train, while her ex-lover tries to make it on his own. The story takes in small town corruption, blackmail and a touch of medical marijuana. A fun, quick read, like all of Cruisie's books.
C. J. Cherryh Cloud's Rider.
Neal Stephenson The System Of The World.