Ironwoman,
I have 2 brooks (b17 and team pro) and agree they are extremely comfortable
once broken in.
I've recently tried a Fizik Aliante, and I'm seriously impressed. Lightweight
comfortable and fits like my team pro.
Fizik also makes a Tri specific saddle (Arione Tri) with a bit more padding
on the nose of the saddle.
I have no experience with any of the Arione saddles so I can't speak about them
other than to say that the Ariones also get great reviews.
If you are going to stick with Brooks give Bill Laine at Wallingford a call he
will be more than happy to discuss different models with you. With his 6 month
guarantee you really can't go wrong.

marty