For non-native English Speakers

• What language do you think in?
  • English and Dutch, like Hurrycane said, it's a lot easier to think in English than it is in Dutch. Dutch grammar is extremely confusing, whilst English grammar is a lot easier and goes automatic for me.
    People around me also speak Dutch, and depending on where you are they use some English words. Pinapple is a commonly used curse word too, yet it's concidered one of the "softer" ones.
• What language does your family speak?
  • Dutch. We're living in our native country so we're constantly using our own language.
• What language do you dream in?
  • I don't know, it's been a while since I actually remembered a dream. But I think the last time I did I dreamt in Dutch.

Personally I prefer English over Dutch, as it is an easier language and doesn't change as often. (Dutch orthography does change a lot, and the grammar is very complicicated.)
Like Hurrycane said, Dutch is a Germanic language, so it's easy for us to understand German. It's a bit harder to speak it though.