Yep portrush is the go. There are plenty of different breaks up there, Portrush west strand is probably best for sup. There are plenty of breaks on the north west coast too - Bundorean/ Rossknowlagh area. If Mullagh is firing its worth a look!
Don't forget Bushmills whiskey, the oldest distillery in the world is 10 mins from portrush and you'd be a fool not to get a Black Bush up there