First, I would say that Montenegro is perhaps the most beautiful country in Eastern Europe. In Europe overall, I'd give the prize to Italy.I would like to ask a small advice. I'm going to Montenegro (flying to Dubrovnik) with my boyfriend for one week vacation in August. It's a bit your "fault" because it was you who told me that Montenegro is the most beautiful country in the Europe. And last summer I've spent a long weekend close to Zadar and I really liked Balkan. Which places exactly in Montenegro would you us suggest to visit? We started to revise Lonely Planet but seems that there are lot of thing to see and it's not easy to decide.
Montenegro has good competition in Eastern Europe, including Croatia, Slovenia, Czechia, Poland, and Romania.
The best place to see in Montenegro is the coast, especially Kotor Bay. Nearby you can visit the cute town of Perast.
A bit farther is Budva (outstanding), Herceg Novi (pretty good), and the monastery on top of Mount Lovcen (awesome!).
Then even farther, if you have time, visit the Lake Skadar and Durmitor National Park.
Have fun!