Thiago Alves is a dangerous fighter, but at the end of the day I still don't see him beating GSP. Not even close.
There are a lot of people underestimating Thiago. I think without the Serra defeat then you would have to probably say GSP is the best. But it did happen. And if I'm looking at dangerous opponents I would rank Thiago waaaay higher then Serra. Plus its gonna be a lot harder to push a big guy around.
So we shall see...