I read The Decameron and The Canterbury Tales at around the same time, and as collections of medieval stories go, this one wins by a landslide. The translation by Mark Musa is very accessible and the variety of the material is just about unsurpassed. There are tragic tales of loves lost and unrequited, even a story about a woman who puts the head of her dead lover in a pot of basil. (MMm. Spicy!)
The comic stories are my favorite, though. The Decameron spins colorful yarns of adulterous lovers pulling tricks on unsuspecting husbands, practical jokes involving pompous religious figures, and enjoyably naughty tangents like the one about the solitary monk and the young temptress who shows up at his cave.
It's over 800 pages long, but there's so much diversity I really didn't notice. Good stuff.