Definitely De Struise. This doesn’t mean that I think all De Struise beers are better than all other Belgian beers. I too find it hard to top Rochefort 10 and I am a huge fan of a wide range of Belgian beers.
De Struise is my favourite brewery because they continue to innovate, make new and exciting beers and participate heavily in the beer festival scene. Plus the brewers are really nice guys and great to talk to. Urbian encouraged me to start doing my own (home) brewing and that has just been a fantastic part of my life.