I will be stopping off in Belgium Tues. May 30, on the way from Paris to London. I arrive in Brussels at 0915 and will need to be checking in for Eurostar to London about 1700. Loving art, architecture, cities, and government, should I stay with tentative plan of taking the HOHO bus in Brussels to catch an impression and visit Parlamentarium and art nouveau architecture, or would it be better to go to Ghent to check out the famous altarpiece and let Brussels be completely incidental to that? I've heard there can be waits at the Saint Bavo Cathedral where the altarpiece is located. What is the current experience with that?
I saw the Ghent altarpiece last May. The line was very short, maybe 10 minutes wait at most. And I imagine Tuesday isn't the busiest day.
With 8 or 9 hours, would it be better to ride a train an hour each direction, plus the tram ride each way to St. Bavo (it's not really walking distance from the train station) than to spend the entire time seeing Brussels? I guess it depends on how thrilled you will be to see the altarpiece. If it's a bucket-list item for you, maybe it would be worthwhile. And as long as you're in Ghent, there are many other things worth seeing, including just exploring the city. (Rick has a great walking tour in his guidebook.)
You should also be aware that the Ghent altarpiece is currently undergoing restoration. You can see the restoration work in progress at the Museum of Fine Arts. At any time, several of the panels may be removed from the altarpiece and at work in the museum, which is closer to the train station and not walking distance to St. Bavo. I believe there is a plan to open a new chapel at St. Bavo to display the altarpiece after the restoration is complete, a few years from now.
There is much to see in Brussels as well, and you wouldn't have to lose so much of your day in transit. But only you can say which would be better. And with 9 hours, you would have time to do much more than catch an impression. You could visit the Royal Museums of Fine Arts, the Musical Instrument Museum, and lots more.
Note that the train to Gent still requires a walk or bus to the "old town" center. Gent is a great visit, but based on your stated interests, there is no reason to leave Brussels. (Brussels is FAR from my favorite city in Belgium, the point is your subject line "Seven-Eight Hours."
Brussels has several superb museums, especially the Ancient and Modern Art Museums and (if you're interested) the adjacent Magritte Museum. The first pair (attached buildings) could take an art lover four hours just to scratch the surface. A short walk away is the varied and interesting Bozar, which seems to be a combination of touring loan shows, ethnography, modern and contemporary art, and trendy ideas.
This doesn't even mention the traditional tourist stops, like Grand Place, Mannekin you-know-what, the beer museum (!), and so on. The two specialty museums, also walkable, the ancient palace basements (Coudenberg) and the history museum (which does not cover up King Leopolds exploitation of Congo) are good too. The Musical Instrument Museum and the Comic Strip museum are heavily visited.
You have a lot of research to do to make the most of seven hours. Don't forget time for Immigration formalities at the Midi rail station, allow a half-hour at least. Everything in this post is walkable from Gare Centrale. Forget about the Atomium and the European Parliament.
If you only have 7-8 hours, I'd stay in Brussels. You just don't need the stress of going to Ghent and back and still making your connections. Since you love government, I would definitely go to the Parliamentarium visitors center and if time, also the tour of the EU Parliament which is marked "Hemicycle" on the signs. The Parliamentarium is a high-tech museum the extols the virtues of the EU and its parliament. It was practically empty when I was there, and some of the exhibits are heavy on propaganda, but still it's a fascinating sight if you love to learn about governments. The Parliament chambers tour is done with an audioguide and takes about 20 minutes. When I was there, it was just a 10-minute wait to get in. By the way, be sure to bring your passport with you if you want the tours the chambers.
Brussels also has wonderful art nouveau architecture. If you have the time, I'd book a bus tour that covers it. If not, go to the Musical Instrument Museum, which is a fascinating art nouveau building that originally was a department store.
Don't forget that Brussels has fabulous restaurants--save time for a scrumptious lunch.
reiterating - check in for your Eurostar early enough to meet their check in / security check / Belgian border control / British passport and border control / getting to the platform / visiting the choccie shops - all of which is a bare minimum of 30 minutes, I'd allow nearly an hour - or they won't let you travel.
Thanks for all the great help! Yes I know a generous allowance for Eurostar check-in stops must be made. I think maybe it's best to stay in Brussels and do more detailed research on what to see there.