I use the same saddle on all my bikes as I found one I liked and was happy to stick with it and it works well on and off road. I agree with SadieKate in that you need a saddle you can get off the back of but is also long enough to move forward on (I've struggled with stupidly short and wide women's saddles in the past).

I ride a men's flite gelflow, nice and long and very supportive of the sitbones and no soft tissue problems. I've found the length of it beneficial on the road bike as well as it allows me to move around a bit as coming from an MTB background I'm not used to sitting in the same position for long periods.

My friend uses a Jett (a 130mm one) on her MTB and really likes it. I really liked it as well as it was lovely and narrow and didn't at all get in the way of my "sporty" thighs but I couldn't justify buying more saddles.