Superman All-Stars #1 & 2, The Dark Knight Returns, Hush: Vol. 1, and Batman: Gothic to be exact.
Dark Knight Returns was "Holy Crap!" kind of excitement for me. I got so excited and jittery in front of all of my friends that it was embarrassing. A very fanboy moment. I just couldn't believe what was happening...
Hush was a little strange, but very brave nonetheless. Can somebody explain the Oracle to me? Is it a computer in Batman's suit? I loved how Loeb took a lame villain like Killer Croc, and made him cool.
Gothic was very, very dark, and I loved it.
The Superman All-Stars series is very fun and very adventurous. I hope it continues to be this good.