What shouldn't be missed in Bruge, Gent, Brussels? (food, beer, etc)
Should have asked earlier, what sort of beer(s) do you and the rest of the party prefer?
Be sure though to give the genever a try when in Gent, it's fairly easy to find there but can be difficult elsewhere and the more Walloonian the harder to find in my experience. Similar to Gin but there are noted differences. From a previous post and may help you on several counts.
Some thoughts for Ghent:
Be sure to hit Temmermans along Kaanlei for some candy! Also hit the smallest bar at least in the city, rumored to be in all of Belgium as well. 't Galgenhuisje @ Korenlei #5, has quite a ncie selection of beers and a good spot to stop for a bit. If the weather is kind, their patio is quite enjoyable.
For a different bit of food fun, stop by Tierenteyn-Verlent - a Mustard shop, close by t'Galgenhuisje but at Groentenmarkt #3. They make it quite faithfully and will explain a good bit about the spice.
In Bruges for food, I would suggest: De Vlaamsche Pot which is an out of the way place - first time we walked past it twice before we figured out where it was - no GPS. Service has always been good for us there and the food also good. Can run a bit pricy though. http://www.devlaamschepot.be/ The waterzooi and stoofvlees were very well enjoyed as well as the waffels on a different day - afternoon treat.
I don't know what kind of restaurants etc you are looking for, but Bruges has some Michelin-starred restaurants that are really good. If you can afford it, check De Karmeliet (or otherwise De Refter, the cheaper bisto-version next door), Hertog Jan, De Jonkman or De Herborist. They won't disappoint you. Check The Chocolate Line for fabulous chocolate (you'll get the same at the star restaurants). Trappist breweries are always inside abbeys, that's why you can't visit them. But De Halve Maan (http://www.halvemaan.be) - the city brewery of Bruges - makes a perfect alternative. Den Dyver serves a special beer menu, which is really good.
For local specialities, I can recommend Chez Leontine in Gent (fantastic beer list by the way). Het Trappistenhuis is a very nice pub to discover Belgian beers.
The choice in Brussels is overwhelming for food. Viva M'Boma is surprising. To combine great fries with typical Belgian food (great mussels) & atmosphere, go to Friture René. Go to Cantillon to taste the best geuze in the world.
re: Bill Shankly
Friture René is a great suggestion. Certainly off any tourist trails - but metro station Aumale gets you there. Great Belgian food (also top class oysters from France) and a good democratic wine list makes this somewhere special.
No web site, will not always take reservations and payments are cash only.