Gödel, Escher, Bach: An Eternal Golden Braid by Douglas Hofstadter
I'm not that far in to it, but I can't put it down. I read The Prince by Machiavelli on my way home from vacation.
The GEB is an old favorite.
Presently reading:
The 'Color of Summer', Reinaldo Arenas, I recommend anything of his.
Also 'The Long Tail', Why the Future of Business is selling less of more, Chris Anderson.
Previously, 'Evening in the Palace of Reason', Bach Meets Frederick the Great in the Age of Enlightenment, James Gaines,
'Last Summer', Michael Thomas Ford,
'The Habsburg Monarchy', Robin Oakey.