Nick Watt says "take a taxi" then states it's expensive. Take a train (every 15 mins) to Brussels main stations (North, Central or Midi) for only €1.25 with a Key ticket (€10.00 for eight journeys)or €2.60 single fare - ± 10% of the taxi fare!
Updates
Train is €5.20 single these days, but still much cheaper than taxi. 10 journey carnet for the tram/metro €12.50 (March 2011)
Is this your business?