Combinatorics: In my opinion, Discrete Mathematics is only a mediocre journal (I wouldn't consider this top journal). Yes, it contains good papers, but it contains a lot of papers... on average... it's average.
Some other ones worth a mention (on top of JCTA, JACO and EJoC mentioned earlier): Journal of Combinatorial Theory Series B, Journal of Combinatorial Designs, Annals of Combinatorics, Combinatorica
The Electronic Journal of Combinatorics should probably go on the top list in combinatorics, but since it's a free, open access journal, it's usually assumed to be worse than it actually is.