Will be taking a day river castle cruise from Mainz to Bonn. I would like to spend the day in Bonn. What should I not miss. I know that is where Beetoven's house is. Any other information would be appreciated.

Assuming that it is NOT Monday, go to the Museum Mile south of the Aldstadt where there are four museums. The best one is probably the House of the History of the Federal Republic of Germany. If you are into Greek and Roman sculpture, head to the Academic Art Museum.

In addition to the Beethoven Haus, there is the Schumanhaus, the sanitorium where Robert Schuman checked in after trying to commit suicide.

Thanks,
Any other suggestions on good food and drink, churches, and monuments

Bonn's cathedral is quite nice, and there are lots of place to eat downtown.

A favorite of mine in the Bonn area is Augustusburg Palace, in the town of Bruehl, about half-way between Bonn and Cologne. Great rococo castle with large gardens.
http://www.schlossbruehl.de/deu/augustusburg/

For me, I would recommend the Sudhaus Friedensplatz 10, near the Aldstadt. 27.40E for two, with wine. Fantastic food and good local flavor-some tourism.

Thanks everyone for the great info.
Will not be leaving till next October. I am off to a great start.
mike