If you want info about Belgium Beers start here https://en.wikipedia.org/wiki/Beer_in_Belgium#Belgian_beer_types
Roughly speaking you have "belgian ales", lambics and sours.
Belgian Ales:
- Karmeliet (Tripel)
- Rochefort 10 (Quadrupel)
- Deus (Champagne beer) (it's a bit expensive, kind of 60 euros the bottle)
- Westvleteren (8 & 12) (12 was considered the best beer of the world, I disagree :) but is great, Rochefort 10 is better to me)
- Gulden Draak
- Orval
- Rodenbach (Grand Cru)
- Dupont (Saison)
- Kwak
- Westmalle (Tripel)
- St. Bernardus (Tripel, 12)
- Carolus Vintage 2000
- Noir de Dottignies
- Pannepot Grand Reserve (flavor half way between Imperial Stout and Barley Wine)
Sours:
- Gueuze Cantillon (In general I'd say go to Cantillon brewery and do the tour)
Lambics:
- Mort Subite (Kriek)
- Lindemans (Kriek)
- Lindemans (Framboise)
- Delirium Cafe (Record guiness, the place that has the most extensive beer menu)
- Le Bier Circus
- Au Bon Vieux Temps
- Moeder Lambic
- Cantillon
- de Garre (http://www.degarre.be/) get their Tripel
- 't Brugs Beertje
- Herberg Vlissinghe (a bar that works since 1515)
- Le Trappiste
- Cambrinus
- De Halve Maan