Depends on what kind of seat you want.
If you want a good comfortable seat that's suited to off road riding, Go with Larryboy's suggestion.
If you want the ultimate in comfort, and money's no object, then call up Russell Day Long Saddles and have them make one for you.
They're not the prettiest seat on the block, but they're the absolute in comfort.
Used a Russell on my 6k trip to the Arctic last month. first day was 820 miles.
Unbelievable comfort. Absolutely no limit to how long you can sit on one and be comfortable.
Russells look like someone grafted a Barcalounger onto the pig. I'd rather have a sore ass.
I guess that's up to you..
When I ride, I'd rather think about how much fun I'm having, rather than think about how much my ass hurts..
But I guess I'm more in tune with enjoying my ride, than worrying about what other people might think of how my bike looks..