This is probably the best movie where Batman appears in, but if we're talking about nailing down the tone, the music, Gotham City, costume, pretty much how Batman should be, I'd say "Batman Returns" is the actual best Batman film. That film is the true essence of Batman.
Batman Returns is my favourite, too. I'd probably follow it up with Burton's first Batman film and Matt Reeves' The Batman before making my way to The Dark Knight and Batman Begins. Although, I'm rethinking it on the fly, and Mask of the Phantasm would have to mosey in there somewhere.
But, for me, the big takeaway here is how many awesome Batman movies there are. These are slim margins for which one is best, we get so many different nuances of Batman, and Bat-fans are really spoiled for choice with epic Batman movies. Like, if you're a Superman fan, you have a couple Christopher Reeves films and (depending on taste) maybe one other movie you sorta like (I like Superman Returns, personally, but I recognize it's a gem with a lot of flaws). Imagine being a fan of The Hulk?
I agree. There are a lot of good Batman stuff out there: Burton's first two films, Nolan's trilogy, Mask Of the Phantasm, The Batman, Batman: Under the Red Hood. And if that weren't enough, Batman: The Animated Series is such a great show that showcases the Batman aesthetic well.