Brussels has international brands' boutiques. See them on Rue neuve with City2 mall and Inno department store (downtown).
For more sophisticated and pricey clothing, rather go to Bd de Waterloo, Av. de la Toison d'or and Av. Louise. Those streets are located in same uptown area (Metro station: Porte de Namur, Louise).
*My favourite places for a one-stop shopping are Woluwé Shopping center (Station: Roodebeek) and Rue des Tongres areas (Metro station: Merode).
Rue des Tongres is less crowded and near my house as well :-). I like it very much since I am a shoe-addict *LOL* and it houses several great shoes' boutiques.
What to buy: Italian and French brands shoes in Rue des Tongres. They are not cheap items but they are really worth it!
Not only in the main street but enter the two galeries (Tiny shopping malls, in fact) as well: Galeries du Linthout, Galeries du Cinquantenaire. Some boutiques sell great names such as Olivier Strelli and Chacock cloth (unusual and colourful style)...
What to pay: Depends on what you buy but I would say shoes from 50 euros to 250 euros.
A must-do after sticky hot summer walks and shopping sprees: discover homemade Belgian speculoos ice-cream.
Instead of sitting at the nearest Haagen-Dazs to refresh yourself, head to a Belgian (sometimes Italian-run) ice-cream parlour. I know some good of them, all located off the "tourist-trap" areas.
The nearest I know is Aux Délices de Capoue. Try there Glace au spéculoos!! Yummy!! It is a Belgian specialty with speculoos cookie and cinammon. Other tastes: rhum-raisin, maracuja, 4 épices, lavender... Located in Etterbeek, close to EU Institutions
In Uccle (Vanderkindere station), head to Zizi and Il gelato for Italian ice-cream. Both are good but I prefer Zizi for sophisticated combinations of tastes. Try Coupe Créole, Bali, Acapulco... (ice-cream of different tastes and fresh tropical fruits, sometimes rhum...). Anyway, go there to discover myriads of combinations.
By the way, shopping is pleasant in Rue des Tongres and surrounding malls. So is shopping in Uccle area (Rue Vanderkinderestraat, Chaussée de Waterloo, Chaussée d'Alsemberg...)
I put it here since it's about refreshing after shopping and walks. I guess it does not matter to not put it in restaurant tips. Belgian speculoos ice-cream is a must-discover specialty.
What to buy: Speculoos ice-cream within ice-cream parlours mentioned above.
At "Aux Délices de Capoue", try, aside speculoos, rose, green tea, jasmin flavours... Their rhum-raisin is to die for!
Skip Haagen Dazs.. Discover something else...
What to pay: Round 5-7 euros depending on combination.