Saddles have come a long way in recent years. Manufacturers like WTB have taken great pains to make sure their saddles are designed both for comfort as well as to compliment your riding style. XC saddles tend to be lighter weight and narrower. A narrow saddle offers you more control during your ride - which you need for freeriding and technical trail too. Open channels in the middle offer relief from saddle soreness. Some offer gel inserts for a plush feel. If weight is an issue, look for a saddle with carbon or titanium rails and shell like the WTB Devo.
"I just placed this order yesterday and it arrived a noon today!!! Incredible - thank you so much, was worried it might not arrive before our trip. -Al"