i use Brooks saddles. once they break in, they're the best thing ever. i've ridden my bike for hours at a time, and it's never uncomfortable. no soreness at all. ever.
they are pricey, though (in the 100-200 dollar range.) but to me, the comfort (not to mention the style) is totally worth it. they're even better when you find one for a coupla bucks on ebay and restore it yourself: