Well that's perfect, because you'd never have to work in Brussels. Try Maastricht! Oh, and Luxembourg for 8-9 months too.
I can speak a bit of Dutch, mainly because I used to go out with a Dutch girl (before I even applied to Eurocontrol). I learnt Dutch because I wanted to impress her... didn't bloody work though. To hell with it, that's in the past now. I speak a bit of French (which came in jolly handy sometimes in Luxembourg). German will alse be slightly useful in Luxembourg.
In Maastricht, everyone speaks English. But sooner or later everyone learns Dutch.