Even though I'm Belgian myself I don't particularly like Belgian cinema and "Ex-Drummer" is not an exception. "Ben X" is a film I found somewhat enjoyable as a reference to living with autism and "Daens" is worth watching if you want to catch a glimpse of how horrible life was for 19th century factory workers out here. Other than those, I don't know what to recommend, though.
No-one recommending "Crazy Love"? I'm not Belgian, and even I recognise that as a classic. It's an adaptation of some of Charles Bukowski's work, and it's amazing.