Definitely loved Julian Jaynes. It's a "just so" story, but quite compelling and interesting - enough so to have a cult following.

Probably the most challenging/rewarding book I've ever read was Fuller's Synergetics. It offers an understanding of science and nature that is holistic in a way that is timeless and self-evident.

http://www.amazon.com/Synergetics-Explorations-Geometry-Buck...

Actually, in contradistinction to buzz-wordiness, most of the terms he used such as tensegrity have quite precise definitions- conceptually, as well in mechanical terms. If you want to get a true introduction to the depth and breadth of his thinking, I highly recommend his magnum opus 'Synergetics' [1]. Otherwise, at least take a glance at the meta-structure/heuristics behind his geometrical and design work [2].

[1]http://www.amazon.com/Synergetics-Explorations-Geometry-Buck...

[2]http://en.wikipedia.org/wiki/Synergetics_(Fuller)