oh yes and you can rent bikes (same system as in paris) in brussels too. it must be possible in bruges and gent too. Bruges (Leuven) and Gent are very cycling friendly cities because the medieval centres are car free. And like Tulip said, bruges, ghent, brussels, antwerp and leuven are very walkable cities. Oostende is nice in the springtime. De Haan is very pretty too (belle epoque coast city).