Arkham Asylum remains one of my all-time favorites. Some other really good ones are Long Halloween, Dark Victory, Dark Knight Returns, Gotham by Gaslight, the Black Mirror, Red Rain/Bloodstorm/Crimson Mist(love those, its an Elseworld story about Batman becoming a vampire trying to fight the curse).
Then there is also the newer stuff like collections of Scott Snyder's excellent run on Batman. Death of the Family in particular is fantastic. Greg Capullo's artwork is also particularly good, been a big fan ever since his
Spawn days. Another recent book is Batman by Doug Mounch and Kelley Jones which collects some really good stories from the '90s Mounch/Jones/Beatty run on Batman(one of my favorites). Hopefully DC will put out a collection of Alan Grant and Norm Breyfogle's late '80s/early '90s run on Batman as well(another one of my favorites).
Anyways there is a lot of really good stuff to choose from when it comes to Batman books. Loved Batman for as long as I can remember!
