Great book, though it covers a somewhat different subset of topics than those typically considered "discrete mathematics"...

http://www.mhhe.com/math/advmath/rosen/ ..is what we used in college; I found it hard to read in spots, but haven't really found anything overall better.

Ordered from Amazon; let's see if I can put that useless BA in math to some productive work...

It's a great book, but not exactly one in the theorem-proof-corollary vein.