Added comfort is a tough benefit to nail down with something as simple and minimal as a seatpost -- you're talking about a few inches of tube is all. It's possible that certain seatpost comparisons might yield a discernable difference, but that's not a quality you can make an informed hunt for.
The biggest things to watch for in a seatpost are 1) the effectiveness of the clamp design, 2) lower relative weight, and 3) the way the damn thing looks.
What's your price range? There are lots (LOTS) of well-made carbon and aluminum options which may make you feel better than your current seatpost, and fit within your wallet.
Deda, Ritchey, ITM, USE, Thomson, Campagnolo, Shimano and Easton, among others, make some sturdy, reliable options.
Someone is bound to tell you, FYI, that there are areas to upgrade your bike which might lead to more dramatic changes in weight, ride, and so on -- stuff like wheels, or a new saddle, or even handlebars with a slightly different bend. They're right. Even so, nothin' wrong with changin' up your seatpost, so long as you know what you're in for. Thoughts?