If your stay is on a weekend, nothing beats the Metropole. Great rate and a fabulous hotel. (Ditch the kids and visit the bar there, it's one of the great bars of Europe, for real, listed in lists and everything.)

Here's the link for the weekend special rate: http://www.metropolehotel.be/EN/exclusivity.cfm

Now if it's not on a weekend, then the Metropole is way spendy. But on the weekend, at 119 euros a night, it's fabu.