Belgium is just excellent,
I have been a good few times, at least once a year.. the best time i have found to go is around Christmas time, as all the breweries make their version of a Winter beer, normally a little stronger and a little more special,
What i tend to do is try a different beer every chance i get (which in Belgium is very easy as there is such a vast choice)
There is a couple of great places to pick in Brussels but if you can get out to Brugge i believe its the best, its a smaller town, but there is two or three great bars with a massive selection, friendlier bar staff than Brussels as in Brugge you have alot more flanders and alot less French which i have found are not the friendliest people.
my favourite beer so far in my many trips is a beer from the "halve maan" brewery in Brugge, Actually if you go for the tour its a great tour.. they make an unbelievable quadruppel called Straffe Henrik.. what i find about a few of the super strong belgium beer is that the flavour is taken over by the candy sugar they use.
In this beer its a super nice malty taste with less candy sugar flavour than most, its like liquorice, spices and just a beautiful beer. Do sip this one as its 11% ABV.
Actually writing this post is making me want to go back there right now. Roll on August.