In the interests of making sure that every option is voted for at least once... I say go for the Allez.

As a Cross Check owner (set up with slicks) I don't see much of a point in going for the Roubaix / Secteur. They feel "dead" compared to the CC and aren't any more comfortable. I'm not sure they offer a significant performance increase either, though that depends a bit on the CC setup, what speeds you ride, what distances you ride etc.

I recommend the Allez (I picked up the Elite recently btw), with the Tarmac as a distant second. You'll get a different ride feel with these bikes (one comparable to a good steel road bike), and can still set them up almost the same rider position as the Roubaix/Secteur. The Allez and Tarmac are nearly identical bikes -- same components, same geometry, same frame shape, same wheels, nearly the same weight.