The suit from Dark Knight gets points because it was the first one that allowed him to actually turn his head. But I think I have to go with the BvS suit because of its comic accuracy and it’s the first cloth/fiber based suit since Adam West.
I have to go with BvS. I also have to give a shout out to the Batman & Robin arctic suit. I know it was only used to sell toys but I still think it looks great. Plus it actually makes sense for the movie and you finally have a alt suit you that’s in the movie.
I’ll definitely second the Batman V Superman suit. I think it has the best blend of feeling the most comic book accurate and still looking good on cinema.