Eden said:I have a "utility" bike that has one of those - I couldn't tell you what sort of comfort difference it makes - too much other stuff about that bike is different - big wide, low pressure tires, etc. but I couldn't say I'd recommend one on a road bike. You'd be introducing a lot of inefficiency, putting a lot of your energy into compressing the seatpost rather than into your pedals.
Eden, that is not entirely correct. If you have shocks when you pedal you do waste energy on compressing them. This is because when you pedal you press downwards on the the pedal which puts a downward force on the frame and when the tires resist moving down because of the ground, the force compresses your shock.
This does not occur on a seat because your pedaling force acts on the frame. The seat is merely sitting on the frame and you are sitting on it. You propel by pedaling, not by pushing down with your butt.
When you pedal, your will actually be removing weight (downward force) from the seat. While this does not affect anything it does show that pedaling would not compress any give in the seat/seat post/seat post shocks.
As far as my suggestion on making your ride a lot more comfortable? Pick up one of those over the seat gel seat covers from fleet farm. For your hands I would pick up a nice set of corked tape off ebay (~$10 shipped) and wrap your bars. If you want you can double wrap them (in many there is an extra set of strips that is used to cover the brake or something like that - I put this where my hands sit before wrapping so it add extra padding there).