I use a seat by Wilderness Trail Bikes (WTB) called the speed she. http://www.wtb.com It's got nice padding for the sitbones and a channel for "everything else". I'm not using padded bike shorts and it's comfortable enough - recently did 26 miles road and a 19 mi. MTB with no pain. Here's their description:
The high comfort, female-specific Speed She saddle was developed by female WTB employees years ago for their own personal needs. Since then, this recreational saddle has skyrocketed in popularity, and for good reason. With a shorter nose, low profile internal seams, and well radiused soft corners, women are allowed greater freedom of movement and can enjoy more comfort on longer rides.