A couple other options that have proved reliably good.
Belga Queen - Graslei 10 around the corner more or less from C. L. also on the canal but I think more directly. There are two of these - one in Brussels and one in Gent. Gent has the better of the two. http://www.belgaqueen.be/home.asp?city=2&Lang=1
BQ is for sure more upscale though so if it's casual you are wanting, this is not the place most likely.
Same canal/river as Belga Queen but opposite side and by the bridge is a place called the Crypt. http://www.crypte.be/ I tried this one because during the fest this year - I bumped into some friends also out who had reservations. The place was good enough to build the table for four not two out on the patio by the canal - they had room but just - it was busy - and we were early also. Food was very very good and Flemish. I would think like dinner their lunch would be quite good as well.
Be sure to hit Temmermans along Kaanlei for some candy though! That and the smallest bar at least in the city, rumored to be in all of Belgium as well. 't Galgenhuisje @ Korenlei #5, just at the end of the meat hall which is now basically an exhibition hall has quite a ncie selection of beers and a good spot to stop for a bit.
For a different bit of food fun, check out Tierenteyn-Verlent - a Mustard shop, close by t'Galgenhuisje but at Groentenmarkt #3.
In any case, how about a trip report?
I guess Chez Leontine might be the place you're looking for. Their Gentse stoverij (Ghent stew) is fantastic, the Waterzooi (another Ghent speciality) also very good. You won't leave hungry nor bankrupt. Moreover, they have a great beer list! If you're lucky enough, you can eat outside, next to a small canal.