Lonely Planet has just released an overview of their top 50 "hidden gems" in Europe called Secret Europe. It is available free of charge for download. Lo and behold, Olomouc is number one. Here's what they say about it in case you are too busy or lazy to download (it's free, so I assume it is fine to copy and paste):
Discover a New Old Historical Capital
Location: Olomouc, Czech Republic
As countless tourists embrace the overt charms of Prague and Český Krumlov, the city of Olomouc (olla-moats) is practically unknown outside of the Czech Republic, emerging as the travellers’ equivalent of a special restaurant that is your own little secret. The main square counts among the country’s most charming, surrounded by historic buildings and blessed with a Unesco-protected trinity column. The evocative central streets are dotted with beautiful churches, many of which play host to a thrilling history. Explore the foundations of ancient Olomouc Castle at the must-see Archdiocesan Museum, then head for one of the city’s many pubs or microbreweries.
p.s. Take it with a HUGE grain of salt, as Prague, which is certainly not hidden, is 32nd on the list (for its cafes).