Kristen Philipkoski at Wired has a great report on progress using stem cells to regrow injured or surgically removed tissues. Stem cells, which exist in many places (possibly all tissues) in adults, contribute naturally to injury repair in places like the skin and liver (I'm sipping a beer as I write this), and enhancements of this natural ability may be the first clinical applications which come from understanding of these cells. The improvements that Philipkoski covers include stem cell-produced fat cells for breast reconstruction, and possibly skin stem cells to reverse the signs of aging.
But all of this is too shortsighted. Any reader of Douglas Adams is going to want stem cells for what they can really do. In short, I want antlers. Get me some neural crest stem cells, ply them with fgf and whatever else is coking up the springtime brains of male ruminants, and implant those suckers under the skin of my forehead. Now we'll see who gets the last croissant.
Actually, the triceratops frill was also probably crest cell derived. Yeah, baby.
Makes it a problem to get in the car though. Hmm, the price of leadership.