Patriotism has never been a dirty word. Misuse of the words "patriot" and "patriotism", though, has stained the words to the point where they're immediately associated with something being covered up (see: USA PATRIOT Act).
Nationalism, though, has been a dirty word since the '40s when nationalism's big brother "Fascism" became a bit of an issue for people living in the countries immediately adjacent.
Having pride in your country because its something to be proud of is patriotism, a patriot strives to improve his country.
Demanding your country is recognised as superior without merit is nationalism. A nationalist seeks to belittle other countries to make his own look better.
A patriot does not mind people criticising their country, a Nationalist or Jingoist does not permit any questions about his beliefs.
I just got back from Holland. contrary to popular American views is actually a nation of people who are very proud to be Dutch, I think the confusion comes in the way the Dutch express their patriotism. Everywhere I went I was asked "You are from England, how are you enjoying Holland". Hell, even the Dutch customs officer asked me how my trip was on the way out of Schipol. The Dutch take great pride in their hospitality and friendliness. Because of this, they are actually quite open to criticism, seeing it as a means of improvement (or at the worst, know when a critisim is not valid and should be ignored).
Even though I'm technically an Australian, I really dont mind being called English (I live there now). It happens all the time in the US, I consistently am asked "What part of England are you from" (which should be "which" part) and respond with "I'm from this small island a bit south of England called Australia". Well I guess I cant use that one any more. Sorry for the Grandpa Simpson story, and yes I did have an onion tied to my belt, which was the style at the time.
So it's a shame that I have to use my own country as an example of nationalism, particularly as nationalism pretending to be patriotism. Traditionally, for an Australian to be proud of Australia, we were proud of its accomplishments, accomplishments that often outshone larger nations. It was always an easy going pride, the idea was that you didn't have to wave a flag or recite a poem to be a proud Australian. The Australian way used to be giving people a fair go, being kind and generous to your friends. Sure it was always cliquey but nowhere near the level of outright xenophobia you see today. The people in Australia who label themselves "patriots" are nothing but xenophobic ultra-nationalists who have adopted ironically un-Australian sayings like "Fuck off, we're full", make barely coherent arguments about "boat people" who are allegedly "destroying the Australian way of life" and "taking jobs from Hard working Australians" (lets ignore that the speaker has probably been on the dole for the last 4 years).
Sure I know plenty of people who like Australia, who would like to express their pride, but are too scared of being associated with the likes of Reclaim Australia because... because to be frankly Australian about it, they aren't racists fuckwits like One Nation and Reclaim Australia.
I see the same thing here now I've lived in England for a while. There's lots to celebrate about English culture (not the food, but I digress) however nationalists like the EDL (English Defence Leauge) make it hard for ordinary English to do this because they deliberately try to weld being a proud Englishmen to a xenophobic ideology... And I think that's a bloody shame.