Brussels is split into nineteen communes or gemeenten (municipalities/boroughs).

Bruxelles/Brussel - Brussels encompasses many charming and beautiful attractions, with deeply ornate buildings on the Grand Place/Grote Markt, and a fish-and-crustacean overdose of St. Catherine's Square (Place St-Catherine/Sint-Katelijneplein). Stroll along, (and stop in for a drink) at one of the many bars on Place St-Géry/Sint-Goriksplein, or max out your credit card on the trendy Rue Antoine Dansaert/Antoine Dansaertstraat.
Ixelles - Elsene - A vibrant part of town with a high concentration of restaurants, bars and other services to satisfy the good-looking or the heavy-spending. Some wandering around will reveal small bookshops, affordable ethnic restaurants or independent record shops tucked away in side streets. The Matongé district just off Chaussée d'Ixelles/Elsenesteenweg is the city's main African neighbourhood.
Marolles/Marollen - Not a municipality, but a neighbourhood (part of Bruxelles - Brussel) close to the city's heart. Although this was one of the few places where the Brussels dialect which is a dialect of Dutch (also called Flemish) could still be heard, it is more common in the outer districts of Brussels Capital Region. The area is best known for the flea market held daily on the Place du Jeu de Balle/Vossenplein as well as a plethora of shops selling everything from old radios and bent wipers to fine china and expensive Art Nouveau trickets. Visit on Saturdays or Sundays.
Saint-Gilles/Sint-Gillis - The city's bohemian epicentre with thriving French, Portuguese, Spanish, Maghrebi and Polish communities. The area around the Parvis de St-Gilles/St-Gillisvoorplein is the arty part, with the area around the Chatelain/Kastelein and the Church of the Holy Trinity being decidedly more yuppified. Like Schaerbeek, Saint-Gilles boasts several Art Nouveau and Haussmann-style buildings.
St-Josse/Sint-Joost - The smallest and poorest commune not only of Brussels, but of all Belgium, this commune might not always be too pleasing on the eye but does have a few small, welcoming streets. The mid-part of the Chaussée de Louvain/Leuvensesteenweg is also home to a relatively small Indo-Pakistani community, so this is the place to head to for a tikka masala. The Turkish community which was the largest community only a few years ago has declined rapidly, as they moved to relatively wealthier communes by St-Josse/Sint-Joost "standarts".
Schaerbeek/Schaarbeek - While there might be little interest in this commune to the casual visitor, it does host some very ornate Art Nouveau buildings. The Chaussée de Haecht/Haachtsesteenweg is also the heart of Brussels' vast Turkish neighbourhood. It has more Turkish restaurants than you can shake a pide at.
Jette - Jette, together with Koekelberg and Ganshoren, are three communes in the north-west of Brussels. These green(-ish), mainly residential communes house the Basilica of Koekelberg on their shared territory.
Uccle/Ukkel - Brussels' poshest commune. Green, bourgeois and starched like all posh communes should be. Uccle has retained many of its charming medieval cul-de-sacs, tiny squares and small townhouses as has nearby Watermael-Boitsfort/Watermaal-Bosvoorde.
Molenbeek - Commonly known as Molenbeek-St-Jean or Sint-Jans-Molenbeek. A commune with a very large Moroccan and, lately, Romanian population. With a reputation for being unwelcoming, if not downright dangerous, this is a place few locals venture to - let alone tourists.
WSP/WSL - Woluwé-Saint-Pierre/Sint-Pieters-Woluwe and Woluwé-Saint-Lambert/Sint-Lambrechts-Woluwe are two communes at the eastern end of the city. Mainly residential, with a mixture of housing blocks, quaint neighbourhoods and green areas this place is well-loved by Eurocrats and other professional types. The enormous Wolubilis cultural complex is well worth a visit.