I personally would get the MFT/3 first -- this adds another element to cutting with your TS saw, making it even more useful plus you get a great table for so many other things, even to make using your Domino easier. The MFT/3 is my most used Festool, followed by one of the CT's. In fact these two tools are so important in my workflow I ended up adding an additional MFT/3 recently so that I have two of them as well as another CT to make portability, configuration, etc... easier. This is not to say that the routers are not great, because they are, but for the work I do the MFT/3 would be more important. Of course if you have a dedicated cutting table or place to use these other tools then this might all go out the window in which case the router might be a better choice.
Scot