I think this is an interesting thread since one of the most popular bikes right now is the Specialized Roubaix. Besides it being carbon with all the vibration dampening stuff the big selling point is its more upright riding position. The Cannondale Synapse has the same selling point. Some pro riders are even opting for the Roubaix over the Tarmac for its more comfortable position. I've read that some believe that a more comfortable position will give you better performance than trying to cram yourself into the most aerodynamic position.

Point being flipping your stem into a positive angle will give you the same upright position these bikes offer and people are dropping big bucks to acheive.

I have a specialized stem that allows you to adjust the angle from +16 degs to -16 degs. It has been great for me. The stronger I become the more I can adjust the angle down. Check it out: http://specialized.com/bc/SBCEqProduct.jsp?spid=9870