By my sig, you can see my bias. But I also agree with Beko that a stock cruiser saddle can be nice. Just about any will do if your rides are short, say, under 35 miles.
B66/67/68 and 72/73 for upright bikes (road modified MTB's, classic 3-speeds and cruisers)
B17/Flyer for semi-upright (relaxed geometry road bikes, road modified MTB's, etc.)
Team Pro/$wallow for race type.
There is considerable cross-over use between the first two categories. Pros and Swallows are quite specialized for aggressive riding. They can realy pimp a retro race bike.