The
Great Books of the Western World series by Encyclopędia Britannica and the University of Chicago was big in its day. I bought a set of them about 40 years ago and got quite a bit of use out of them. I'd imagine that everything in them is available for free online these days, but the accessory volumes,
The Great Conversation and
The Syntopicon, were quite good. Excellent quality and binding, still available on ebay last time I looked (several years ago).
http://en.wikipedia.org/wiki/Great_B..._Western_World