I'm suprised no one has mentioned Ken MacLeod's _The Cassini Division_ now out in hardback in the USA. This is a remarkable novel. It deals with several issues of Extropian ethics with such familarity that I would expect that Mr. MacLeod has been lurking on the Extropians mailing list for years.
The novel has some plot/logic problems. For example, the author never bothers to explain how the economic system of his Solar-system-wide anarchosocialist society actually *works*. Gee, I wonder why? But, overall it's interesting and entertaining reading. It touches on a variety of Extropian and libertarian ideas, and even includes an amusing spoof of L. Neil Smith's North American Confederacy.
The viewpoint character is vehemently anti-transhuman, so it's interesting to see through her how and why opposition to the transhuman attitude might express itself. I suspect MacLeod shares than a few of his character's attitudes, given the way in which he writes them.
An excellent novel, strongly recommended for Extropian/transhuman readers.