Brooks B17. Bought it last year and it felt hard, but still pretty comfortable from the jump. Now with 1,200 miles or so on it, it is still breaking in. Even after 4 or 5 hour rides, no chafing, soreness, or numbness in the butt or crotch area. Brooks Imperial looks similar in size and shape to the B17, but with a cutout in the middle.
Leather saddles do, however, require some care, but it isn't a big deal. I have treated with Brooks Proofhide twice since I bought the saddle last year. Will probably treat it again soon before hanging my bike up for the winter.