It sounds boring, but I'd rate 98 as the best. Its the highlight of the series imo.
02 was ok, but I haven't really played the Eolith KoF's much to compare.
From what I played i'd say 98, 2k and 96 are my favorite. KoF97 used to be up there too, but I find it pretty much useless with 98 around.. I've sold the cart for this reason. KoF99 got higher in my ranks, I always hated it but since I received the AES cart I 'm liking it more and more. I especially like the futuristic style, soundtrack and artwork of it. In terms of gameplay and roster its mediocre.