I'd recommend the Sheraton Brussells. The area, as mentioned, is going thru some redevelopment but there are several indoor shopping areas, and a pedestrian only shopping area within 5 mins walking distance.
The Grand Place is within 10-15 mins walking distance or a 5 min taxi ride.
My room was large (for European standards) and the lounge served complimentary food.
Service was effecient and friendly and I'd stay there again. The front desk area however can get rather crowded with tour groups.
This property also serves as a regional office for Starwood European managers... their offices are tucked away behind the scenes - FYI.
The Intercontinental hotel across the street is a smaller, less active property. Along with that are the smaller, darker rooms. The front office staff was mediocre and lobby is much smaller.
Between the two, I stay at the Sheraton anyday!