I just bought Wrath of the Lamb, and am totally hooked on The Binding of Isaac again! If you haven't shelled out the $3 dollars for it yet and are even remotely interested, I highly recommend it. It makes everything way more crazy, even more random, adds tons of new items, environments, and enemies, as well as a host of other features. It also automatically provides the new songs if you have previously bought the soundtrack. For three bucks, or eight if you don't already own the game, I must say it is a very solid purchase.