Some input from a (boring ;o) local Plat

4Pts is obviously a bit of a lesser hotel in terms of rooms, overall service, but located less than a few minutes walk from one of the hottest party places in Brussels (Place Flagey). Also very close to upscale shopping area.

If you really want to do the touristy stuff (medieval centre) the SHT is a better choice, even though you'll still need to walk for about 10-15 minutes (Rue Neuve / Nieuwstraat is the best way to go, popular shopping area, but as mentioned earlier some of the parallel streets are a bit dodgy). Party-wise the area around the Exchange (Beurs/Bourse) is essentially just next to the medieval centre.

In the near-term future, the Meridien will become the best *Wood choice in Brussels as far as location is concerned: right in the centre, just across the street from Central railway station