hmmm good question.
i think balmain's big rivals - south sydney and parramatta - have transfered over to the j/v.
similarly, wests' big rivals - manly and canterbury - have transfered over as well.
a big rivalry that has developed since the j/v has been with the storm, especially with the players (slater kicking skando in the head, danny williams king-hitting buckets, mccracken getting spear-tackled).
personally, i get off on beating the dragons and i know a lot of other wests tigers supporters who feel the same way.