I've passed through Dresden a couple of times, although this was the first time I had spent enough time to see the city properly. Considering how badly Dresden suffered at the end of WWII, many of the old buildings, such as the Frauenkirchen, have been rebuilt as they were. The Altstadt, often full of tourists, is particularly impressive to walk through, as are the Zwingergarten next to the Opera house. Dresden is a good place to break the Prague - Berlin journey for a night or two.
Insider Tip:Neustadt - north of the river is an excellent place to go for nightlife and restaurants.
Bestei - Rock formation south of Dresden. Take the S-bahn or Steam boat to Kurort Rathen. Amazing scenery