Was reading Robert Sheckley's Immortality, Inc, and it's brilliant metaphysical stuff, with enough ideas to have inspired half a dozen life-after-death films, plus plenty left over that no one's mined yet. And funny as hell, with an intriguing sense of morality. The plot twists and outrageous effects aren't there to amuse and provoke (though they do plenty of both); they're there to drive home an actual point, about the concept of karma and the idea of taking responsibility.
One thing not a lot of people mention is that Shecklye's prose can be quietly lyrical. His description of the Marquiesas is loving yet specific, not just the sights and sounds and scents but the very feel of the place; you get the idea you'd find the place familiar if you ever dropped by for a visit.