The Former Capitals of Europe Tour

Having cashed in all of our Alaska Airlines miles, we are now in posession of tickets for next year's trip to Europe, which I'm calling the "Former Capitals of Europe Tour." We'll be flying to Venice (which dominated Europe in the 13th-15th centuries) on April 18, and returning home from Berlin (which dominated Europe in the 20th-21st centuries) on May 19. Our itinerary in between is not yet set, but we plan to hit Vienna (which dominated Europe in the 15th-19th centuries) and Prague (which was the capital of the Holy Roman Empire in the 14th century), and will probably also take a tour of the Czech Republic.

This is our second visit to Venice and Vienna, my first and Kate's second to Berlin, and our first to Prague. Any recommendations for sites, hotels, restaurants, events, etc. to see (or avoid) would be highly appreciated.

Whee!