There are a lot of places to visit in the Czech Republic, including the wine region of Moravia, plenty of castles in Bohemia, and more. I agree with @tassojunior on Brno, which is not very charming. Český Krumlov (2 and a half hours from Prague) is an enchanting town, with a breathtaking medieval castle. Olomouc is a very pleasant small city, with a historic central square. I would also mention Kutná Hora in Central Bohemia, about an hour away from Prague. It has a most impressive ossuary, a crypt entirely decorated with skulls and bones, quite unique.
And yes, I lived in Prague for four years.