Hope you have a good time Eeyore,
Brussels is a strange punting place - there are the red light areas or the more elite agencies (presumably for the politicos and their hangers on). As well as Rue d'Aerschot there is the area near the Yser metro (Rue de Laeken and nearby streets). This is more the heroin hooker streetwalker zone, many of them very young. They use a group of what are called 'studio' hotels nearby where you have to pay about 40 euros to hire the room. The rooms are rather squalid (I an told that the beds there must have the world's biggest collection of bedbugs and stains), so it's a rather expensive process. That area has been undergoing a lot of renovation, so you have the street walkers alongside some rather nice bars and a very nice theatre.
Rue d'Aerschot is very much the strip for European girls, many of them quite attractive and mostly European. There were a few old hags as well in windows when I went by the other week. Up from there is a network of road around Rue Dupont, which is the domain of the African women in windows. Here you can find all shapes and sizes. Walking around the areas you do come across a lot of groups of men, but I've never really felt under threat there.
Like many others have said, Brussels is not at all a quality punting place, but it certainly has a lot on display in the windows and on those streets. Annaberry (menioned earlier in this thread) is typical of the expensive, but very elegant upper end of the market. An experience there is one of those where you save up for a special occasion - unless like the MEPs it is covered by 'expenses when entertaining a constituent'.