Found this site/topic by Google searching on my iPhone. Thought I would chip in my two cents. I actually just started reading Batman a short couple months back myself as well, so I'm still looking for some more broad opinions, but I have 38 books myself so far, with probably another 50 on my want list. But here are my recommendations.
Batman: Year One
Batman: The Man Who Laughs
Batman: The Long Halloween
Batman: Dark Victory
Batman: The Killing Joke
Batman: Arkham Asylum
Batman: Knighfall (particularly vol. 1: Broken Bat)
Batman: Hush
Joker
Batman: The Dark Knight Returns
Also not exactly a Batman book, but he is featured in it pretty greatly. JLA: Tower of Babel.
Also I highly recommend Grant Morrison's run starting at Batman and Son up to Batman Inc, with all the side books from other authors that just compliment his story.
Here's my list for ya.....
1. Dark Knight Returns
2. The Long Halloween
3. Batman: Year One
4. Dark Victory
5. The Killing Joke
6. Hush
7. The Cult
Enjoy..... >
They just restarted all the main DC titles so now would be a great time to start picking up Batman, Batman and Robin, Detective comics, etc in singles and start from the beginning.