The Conrad is an awesome hotel, and I managed to get a weekend there for 3800 BEF/night in March (which is just over 100 USD). I felt like they made a mistake or something because the room (probably the cruddiest room in the whole place) was an absolute palace. The marble bathroom was bigger than some guest rooms in London for which I paid more... I would have been happy paying $300/night for that room. Try your luck...
There are some nice museums, and just taking a nice stroll through the city is fun too. I was only there for two days, but don't miss the chocolate... that's about all I can say.