Well we've got one of these threads for Anime already so how about one for books. Same idea really, post your recommendations for books you enjoy.
I'l get the ball rolling with one of my all time favourite series': Terry Pratchet's Discworld novels.
Discworld is a long running series (39 books as of next october) set atop a flat world known only as "The Disc". The disk rests on the shoulders of four giant elephants who are in turn carried through space by Great A'tuin the cosmic turtle. Each novel follows the exploits and adventures of a group of inhabitants of this flat world filled with Wizards and Witches, Dwarves and Trolls, Dragons (although not in the traditonal sense with one notable exception) and Gods who very definately exist and have thunderbolts to prove it.
Each entry in the series can be read as a stand alone installment and Chronological order isn't all that important (I myself started with the 19th installment "Feet of Clay" which is also the 3rd entry in the "City Watch" set) The books can be divided into 8 storylines at the moment. The Wizzard (misspelling intentional) Rincewind, Death (and associates), The Lancre Witches, City Watch, Wizards (Which has sort of absorbed Rincewind since his return to the Unseen university), the Tiffany Aching books (could be considered a subset of the Witches, although with more Pictsies), the more recent Moist Von Lipwig storyline and the other novels which fall under "Other cultures of the Disc" which cover standalone volumes.
The series is an affectionate parody of fantasy tropes with some amazingly clever wordplay and jokes. Despite being something of a parody Pratchet still manages to weave a compelling narative and evolving storyline. And therein lies another charm of Discworld and one of the reasons Chronology isn't too important, the world constantly evolves with each installment. The books are absolutely jam packed with references to the previous ones (and sometimes even to future ones, minor characters becoming important later on etc) and the author never seems to forget any of what he's done before. This makes it an absolute joy to read and reread, Honestly I'd recommend NOT starting from the begining: read one at random from the middle of the series, then go to the begining, read your way through to where you were, reread it and marvel at just how much more there is to it than when you first read it with a pleathora of previously unnoticed references and the like.
The series also manages to provide social and political comentary on current trends (for example "Soul Music on rock music) but in a subtle and well thought out way that never seems to be trying to force a point of view.
Overall its just an absolutely excelent series of books, wonderfully thought out and written, clever and at times insightful and above all HILARIOUS. I'd strongly recommend it to anybody.
I could go on and give more recommendations but its late and I ought to get some sleep (not to mention the fact that if I allow myself to go on much longer this could easilly end up as the Madoka post all over again =p) so more recommendations tomorrow or some other day I guess