Dear Nobi, do not think that there's a war going on in Athens !
There are demonstrations which end up sometimes in violent actions but this is primarily between protestors and the police - people (no matter Greeks or foreigners) that do not get involved do not become targets for anyone !
Yet, i understand your anxiety and would advise you to visit Athens a little bit later, when things will calm down - this concerns only Athens, there's no problem for the rest of Greece ! about 10 years ago
I would not hesitate to travel in Greece just because of the recent demonstrations. Usually demonstrations pop up mostly in Athens. Strikes which close down the popular sites or the ferry lines are generally scheduled in advance and take place for a very limited time. You can read an English -language newspaper to find out what is going on. You might visit Athens and tour all of the important tourism sites without ever seeing any demonstrations, because they will be centered a little way away around government buildings or university. Even there, ordinary people will be strolling by ignoring the action. about 10 years ago