My advice is to demo as many saddles as possible, focusing on some tried and true ones that are very popular. I did some research a little more than a year ago on popular saddles, then tried out a few out on demo, and finally bought one that has been great for me: the WTB Rocket V. I have done a 10 hour ride on it, a 2 day, 24 hour event, and multiple 3+ hour rides.
I then tried to find a saddle for my road bike, riding 12 different saddles from multiple companies--on demo through the Competitive Cyclist demo program--and finally said screw it the WTB Rocket V works best for me so I got another one and put in on my road bike.
When I did my research--on the endurance racing forum--some of the very popular saddles that kept coming up again and again were the following:
WTB Rocket V
WTB Laser
Fizik Gobi (mentioned above)
Selle San Marco
A Brooks saddle (I forget which one)
Go to the Competitive Cyclist website and check out their demo program. You'd get to ride something like 12 saddles. And part of the money you pay goes toward your purchase is you purchase one. I ended up wanting the Rocket V--which wasn't a part of their road saddle program--and they gave me the credit anyway.