Belgium is a very small country with somewhat limited scenery. It's basically flat, with a few rolling hills. Forests are minimal, and they don't have a very long coastline. Belgium has numerous rivers, but in my experience, they tend to smell quite bad.
Belgium is not particularly well-known for its monuments, but if you look, there's some nice stuff to see. Unfortunately, much of it is virtually hidden, as if you weren't supposed to see it. For a more in-depth review, see my journal entry, 6/30/98.
I was only there for a few days, but the weather was crap. Cold, rainy, and miserable, and this was in early July.
Belgium is about on par with France as far as expense, though I didn't find it quite as easy in Belgium to find cheap groceries. It can be an expensive place, but it doesn't have to be.
The one thing I really regret about my trip through Belgium is that I never actually tried a Belgian waffle. I kept hearing from all the travellers in the youth hostel in Brussels that real Belgian waffles were really spectacular, but I never actually tried one. Other than that, though, I'm not aware of any food that's unique to Belgium.
I didn't really spend enough time in Belgium to say much about people. They seemed a little less patient than the French, particularly in the north. Of course, that may be because I don't speak Flemish, and they don't speak English or French.
I found Belgium to be surprisingly dirty. Even the grand monuments were covered in grime from the pollution. The streets had more trash in them than I expected, and a huge portion of the country smelled of either cow dung or raw sewage. Accommodation, however (what little of it I experienced), was quite clean.
It's pretty flat, really. A lot like the Netherlands.
When I first arrived in Belgium, it appeared that the cycle paths were much better than their French counterparts. That opinion didn't last long, though, as I encountered horribly designed, poorly maintained cycle paths on rough roads. Road conditions are "adequate," I'd say, but not great.