Quiet bar (well, it was when I was there) about 10 minutes walk southeast of the centre. The food menu is not extensive, but does the job. The beer menu definitely is extensive, and runs to 150 or more, listed by category and alphabetically to make it all nice and simple.
Vlaanderenstraat 128 9000 GENT
www.brasseriedeus.be
Google map: tinyurl.com/lhpj5o