I agree with those who say these ships are not the way to move forward, but I think it's important to keep Shuttle flights going for a while to support the completion of the ISS. And no doubt these missions will yield valuable data for planning the next generation of space shuttles, which will, I hope, be somewhere between STS and Space Ship One.
NASA really needs a simple,workhorse people-mover and better robotic freighters to really make the most of orbital space, IMHO... they could learn a lot from shops like Scaled, who are redefining space technology without re-inventing the wheel, and the Russians, who have been methodically tweaking their tried & true, simple, rugged hardware with great success.
But it's always a thrill to see a Shuttle launch, and as a pilot, I love seeing a spacecraft return on a runway. This mission won't disappoint, I think...
