This is a very amusing thread I never really realised or even thought about this subject xD
Well my primary language is English and my secondary is Portuguese (know a few others but not the proficient in them).
I guess 75% of the time I think in English even though I live in Portugal and interact outside my house in Portuguese, but still my tough process seems to be English, the only occasion I seem to be working in Portuguese is during study periods and tests.
All my dreams are seem to be in English.