Germany River Cruises - Any recommendations?

I am going to Frankfurt, Germany with my family in April 2005. I am thinking that it would be fun to spend 3 of our 10 days there on a river cruise. Length of cruise is not set. Even the river is not set, though I imagine the Rhine would make the most sense.

Anyone have any suggestions or recommendations?

we have done 2 river cruises. If you are interested e-mail me at highlandpark@mindspring.com and I will e-mail you the trip stories

As the best German ships I would recommend the fleet of Peter Deilmann. They are known as being quite luxurious, having wonderful food and people dress up for the evenings.

Check http://www.deilmann-cruises.com.

If you are in Frankfurt anyway you might board directly there on the river Main. But it is also not very far to the Rhine, so anything on the Rhine or any confluent is within reach. Yet I do not know if there are tours for just three days.