Home to the European Union, Brussels has a friendly buzz and a thriving café and culture scene. No too big, it is also a good city to navigate. Although it's not as full of tourists as neighbouring Bruges, it's a very attractive, old city with lots to see.
When considering weather, remember this is northern Europe, so stick to May to October for good weather. In May the "Fête de l'Iris" has free live music, street art and street food. The first Thursday in July and previous Tuesday sees the "Ommegang", a medieval pageant. The end of August/beginning of September is the athletics event "Memorial Van Damme".
English is widely spoken and food is slightly cheaper in Brussels, as is eating out. A basic meal is around 6EUR, and a main meal in a restaurant: approx. 13EUR. The beer in Belgium is famous, and is roughly 4EUR and soft drinks are 2EUR. Food is good, try the Brussels waffles and the Moules Frites (mussels with chips). Visit "Galeries Saint Hubert - Sint Hubertusgalerijen", a shopping centre built in 1847 - the first ever.
The trip from the airport to central Brussels by train is about 8.50EUR, and takes around 15-20 minutes. The bus shuttle "Airport Line" operated by STIB/MIVB, costs approx. 6 EUR if you pay in the bus, and ca. 4.50EUR in advance, and takes 30 minutes. Taxis are around 35-45EUR and take about 40 minutes into the city centre.
Travellers' hostels will cost about 19 EUR/night, a 3* hotel costs from 55EUR per person per night. A holiday rental costs from about 70EUR.
Public transport is operated by the STIB/MIVB and there's Metro, Premetro (tram - partly underground), trams and buses. Get a rechargeable MOBIB card. a single trip "JUMP", valid for 60 minutes with changes, is about 2.10EUR, whereas paid for on the vehicle it will be 2.50EUR. 5 trips are around 8EUR, 10-trips 14EUR; a one day travelcard 7.50EUR, a 2 day ticket 14EUR apprx; and 3 days about 18EUR. Taxis are about 8-10EUR for the first 3 km, and about 1.80EUR per km after this. Bike hire is available for ca. 1.60EUR per day (first 30 minutes are free), one week costs around 7.60EUR. However, many top attractions are easily reachable on foot as the city is not large.