2007 Migration options

After reading Joel Oleson's post about migration scenario's I was very keen to see what would happen if I attached a existing 2003 content database to the new 2007 configuration. But what amazed me was the fist question during installation of Sharepoint 2007. I could choose whether I wanted a) to gradually migrate from a existing configuration (the heavy customized and large environments) b) just migrate from the existing configuration c) to install this version next to the 2003 version Because I want to attach a existing database I choose option C btw.. the only thing that did annoy me was being prompted for what seemed like hours with the following screen : To be continued... Office2007sharepoint2007Office12