I love my Selle ITalia Max SLR Gel flow saddle which is 143mm wide and has one of the biggest cut-out on the market. I use this saddle on both my road and mountain bike. Be careful, Selle Italia has a lot of names that sound similar to the saddle that I like but are NOT that saddle.

If you can get demo saddles before you buy at your local bike shop, I would recommend that first.