I've really enjoyed my time in Croatia, and what's really been great has been the art and folk art and the various galleries and museums they're displayed in.
Rovinj - At least 3 of the art galleries were in old churches, and one of the galleries had a fabulous view of the harbor and sunsets. The art here is from the Rovinj City Museum, the artist, Ljubo Ivancic.
Cavtat - Handicrafts and artful food. The smell of ripe figs will always bring back memories of the Croatian coast.
Groznjan - a hill town not far from Trieste, and known for its artists - galleries in stone houses and window views of pottery.
Zadar - from semi-nudes displayed in St. Donats to pop art in the back streets.
Varazdin - a walking about festival, art in the park and in the streets.
Zagreb - Still haven't made it to all the museums, but from Street Art to Art Nouveau Buildings to the Interactive, for a city its size it's got a lot.