Good list. Generally most of the teams from Yorkshire don't like each other very much and the same goes for Lancashire. Some of the rivalries are stronger than others though, the main two at the moment are Wigan-Saints and Hull-Hull KR. Leeds-Bradford used to be considered a big rivalry but due to Bradford's decline that's really fizzled out and I think most of the Leeds fans just feel sorry for Bradford now. There are many other less intense rivalries too such as the ones Wireman has listed, which is usually due to teams being in seperate divisions and rarely playing over the past two years. For convenience, I will give a list of the teams and their main rivalries.
Bradford - Leeds, Halifax (both have fizzled out somewhat)
Castleford - Leeds, Wakefield. Bad feeling towards Wigan and Crusaders.
Catalans - N/A
Crusaders - Widnes, and rivalry developing with Castleford this year.
Harlequins - N/A
Huddersfield - Halifax, Wakefield
Hull FC - Hull KR, Leeds
Hull KR - Hull FC
Leeds - St Helens, Bradford
St Helens - Wigan, Warrington, Leeds
Salford - Swinton (unlikely to ever be a competitive match again, so they have no real rivals)
Wakefield - Castleford, Huddersfield, Leeds
Warrington - Widnes, St Helens, Wigan
Wigan - St Helens