The Hungarian botrytis sweet wines from the overripe late harvest furmint grape are not to be missed. They are known as Tokáji. Look for small 50 cl bottles. They are rated with a star code - look for bottles labelled Aszu with 4 or 5 stars (puttunyos) upwards. In some vintages a superior version is produced - essencia. These wines beat Sauternes at value for money any time.
Vintages 03, 05 and 06 are widely available and top class.
The tax free bay at the airport has a decent and reasonably priced selection.
Things not to missed to bring from Prague are typically not discussed on Chowhound, unless you count their Kohinoor pencils, and their delicate cedar perfumed outer ends as almost edible, as I tend to.