In reply to abr1966:
Did a few hundred KMs there earlier this year - was great. Great infrastructure, traffic takes a lot more care around cyclists, and the roads are flat so you can eat the miles remarkably quickly.
I would recommend Ypres, Bruges, and Ghent as nice places to visit and all cycleable between. Ghent surprised me - a bit like Bruges without the tourists. We went in and out from Lille Eurostar terminal.
And as previous poster has said, the beer is indeed awesome...