Where do you think is the best family holiday destination in Eastern Europe?

Need somewhere with beach thats good for kids ranging from 3 to 17. Not too hot but in school summer holidays. Not too lively or boring either! Thought eastern Europe might be a good idea!

Slovenia! It's a true hidden gem by the Adriatic Sea, not too crowded, quite cheap but still very tidy! I spent a fabulous week in Portoroz in the summer of 2007 (lots of spas and warm weather especially in July!), though I can also highly recommend a visit to the pittoresque capital city Ljubljana as well as the more mountainous Bled.

Croatia has Beautiful beaches and a great nightlife for kids. I would recommend Podgora for a not to crowded atmosphere but not empty. Also Podgora is right next to the big city of Makarska which has a super nightlife but crowded beaches.

Pictures,Info, and Hotels

http://www.makarskainfo.com/podgora/