Depends. What blog format are you coming from? What format is the file currently in? Chance are your best bet would be some form of MT type but without knowing more about your current set up, it’s kind of hard to offer you any suggestions.
I will mention though that you’ll need to change the format of your new blog before you do your importing since it’s probably currently setup to UTF-8. You can do this at Dashboard -> Options -> Reading -> Encoding for pages and feeds