Got a Brooks B17 (i think) on my commuter / tourer / beater bike. It's pretty good.
Got a Selle Anatomic NSX on another bike. It's nice, but requires lots of tightening before it doesn't. Then the edges flare a bit. Still pretty comfy.
My current favorite plastic/pleather/non-biodegradable bike seat is the SERFAS TEGU. I can ride it with out padded bike shorts. But when riding w/ bike shorts on my formerly speedy road bike I've got a Bontrager something or other. It's fine for a formerly speedy bike.
hmmm... seriously too much info...