Romanesque cathedral, one of Germany's three "imperial cathedrals" on the Rhine together with those in Mainz and Speyer, dating back to 600 AD that is currently covered with unsightly scaffolding [Sept 2012].
Listen the mythical story of Worms in Nibelungen museum. Notice there is nothing to see in that museum. It's only listening to a story from headphones.
Jewish Bath, Jewish Cemetery "Heiliger Sand" - Holy Sand
River Banks with restaurants
Nice historic Rhine bridge
The monument to Martin Luther and other church reformers.
City Walls
The Park and the manor-house in Herrnsheim. The park was created by Friedrich Ludwig Sckell, who designed the "Englischer Garten" in Munich as well.