I can't choose between Batman'89 and Batman Returns. The costuming and sets were perfect in the first two and it's hard to pick between the two. On one hand, I loved the art deco blend with then current styles in Batman'89. The whole style was fantastic and really seemed like the perfect Gotham City. And Anton Furst's designs were Academy Award winning, least we forget. But I'm not a particular fan of the B'89 suit, it seemed more like a test suit because it was the first one done. But the design of Jack Nicholson's Joker was superb in every way. Great ensembles to go with his flamboyant style.
Batman Returns featured what is still my favorite Batsuit on film. I loved the sleek and industrial design, and it was far more form fitting than the previous suit, it also returned to using the vintage symbol. The design of Gotham was far darker, but it was the perfect opposition to setting the film during the winter time. I also liked the large statues taken from a Germanic style, they looked good without being ridiculous like in Schumacher's movies. Like the OP said, the shots of Gotham covered in snow were visually in awe. In BR, they also kept with the 40s dress style, I especially like Max Shreck's different suits. I'd bring up the batmobile but it virtually looked the same in both films to me.
But overall, I think I'll pick Batman'89 because it was more "Gotham City" to me while BR was just an awesome design. I have a few thoughts on Schumacher and Nolan's designs and look as well but I'll save that for another post.
