Best Chocolate in Brussels?

If they're selling their own products, my recommendation would be Moeder Babelutte, which you'll pass on the way from the Grand Place to the Mannekin Pis. The caveat is that this particular branch of the company doesn't always sell their own chocolate, for what reason I do not know why. Sometimes, they only seem to offer re-packaged chocolate from other manufacturers. They have branches in Brugge and on the coast that do sell their own divine products, however.

If you are only going to be hanging around Gare de Midi, Neuhaus is my favourite of the chains you'll find there. Try their triangular chocolates with cream fillings within layers of chocolate and nougat crunch.

While many people prefer one of the global brands, I find the local Leonidas shops to have comparable quality at a reasonable price. Of course, the best chocolates are in Brugge ;)