I was thinking of stopping their for a day and a night on my way to Bruges.
I like outdoor cafe/people watching.
"I like outdoor cafe/people watching." That pretty much describes most cities in Europe, Ghent included. For people watching, you'll probably see more locals and less tourists in Ghent than in Brugge.
Pretty little town, I did a day trip there when I was studying in Belgium. Enjoyed the castle. Not exciting, but it was nice.
We rode our bikes from Bruges to Ghent one day last summer. We could have easily spent more than our 1/2 day in the city. It has great canalside cafes, a couple of beguinages, which are interesting, plus the very imposing castle. It's definitely worth the stop, if you have the time (of course, Bruges is wonderful). Do check to see which train station is closest to the old city center (they are a bit away from downtown, but the trams will get you back and forth).
Ghent is a nice Belgium town. I would recommend getting off at the Dampoort Station, as it closer to the centrum.
If you want to try Jenever, the local version of gin, Dreupelkot is the place to go. There are over 200 varieties on the menu and the bartender is very friendly. It is located by the canal right off the Groenten Markt and there is a lovely, but smoky, beerhuis next door.
The Caermersklooster offers a free exhibit - you never know what it might be, but it is generally very good.
If you are there on a Sunday morning the old town is full of markets - flower, food, small animal, bird, antiques, and a flea market.
"If you want to try Jenever"... then I would add, you won't want to try any of the local beer afterwards!