I finished Mort and just started Guards! Guards! I have to admit that I'm liking the City Watch a lot better than the Death series, although both are pretty funny.
The Death series gets better--Hogfather is one of my absolute favourite Pratchett books [though I could never pick a favourite, not really]. Night Watch, which I think is the newest in the Watch series, is brilliant!
Am currently reading Jingo, by Terry Pratchett, and The Stars My Destination, by Alfred Bester--two authors whose books I can read again and again.