Anathem

I have to admit, after the first page of snargalfarg I seriously considered giving up, but I'm glad I didn't. Although it takes a while to get your head around the language and world, once you do it the book becomes a fascinating discussing of various philosophies, set against the backdrop of a more prosaic sci-fi story. Having said that, after finishing the book I feel more like I've been to the (mental) gym that read a ripping yarn.

If you like your books to make you think, this one will definitely give you your money's worth. On the other hand, if you want a light read, maybe skip this one...