If you're going to short-hop to anywhere in Europe you have to see Rome, if you haven't already.
Rome was my last city in Europe and I was sick to death of cities and tourists. Rome was stuffed with tourists, but it was still worth it. If you like history at all, it's a must see. Rome blew me away at every corner.
In Belgium, I only went to Ghent and Brussels. Ghent was better by far. It's a really beautiful place, and young with all the university students.
Your the second person that has mentioned Rome to me in the last few months.
Ill add it to my list after lisbon of course :)
Oh yeah. I should probably get my tickets if I'm going to go.