Not who you were asking, but I'm a big Moore fan as well:
* From Hell (Some might be put off by the original comic's black and white art, but there was a recent release that colourised them by the original illustrator)
There are the obvious ones: From Hell, V for Vendetta, and The Killing Joke, but I especially enjoyed his interpretation of Superman in For the Man Who has Everything and Whatever Happened to the Man of Tomorrow?, which are 2 of my favorite Superman stories.
But I most appreciate him for Swamp Thing, because that’s where we got our first appearance of John Constantine.
* From Hell (Some might be put off by the original comic's black and white art, but there was a recent release that colourised them by the original illustrator)
* Providence
* Jerusalem
* V for Vendetta