In Norway, we owe a great deal to the romantic nationalists of the 19th century. They wrote down and preserved much of old norwegian culture like information about dialects, customs and old folk tales. A great deal of our national treasures in poetry, art, litterature, music and so on come from the romantics. There's also the matter of our independence from Denmark/Sweden.
Today, nationalism may have a bad ring to it in some countries - certainly in Germany for example. Here, being pro and proud of your country and cultural background has few negative connotations.
The celebrations on our national day, the 17th of may, would probably scare some people ..
Of course the average norwegian is only a true nationalist once a year or so. If it's something you occupy yourself with constantly, then you may be a little screwed up in your ideology I guess.