This all sounds great, glad you guys are up for it. We definitely want to show off different styles, I agree 100%.
On SDL: I refreshed the SDL page, I see they are from a pool, but the pool doesn't seem that big (maybe 20 games max?) They all seem like commercial games too, and the promotion image is not a screenshot. So I think in this sense it has a different agenda, it's saying "all these great games are made with SDL, you can trust that SDL is capable." Which is different than saying "here's some screenshots, you can make things like these."
So I guess there are two different angles this could be approached from. The good thing about the SDL way is it doesn't matter what style the game is, as they just show the promotion/cover image. It's the fact the game exists, and you can click the link and check it out, that is important there. So maybe we should approach this the same way?
Whatever you choose to do I think we all agree that it'll be nice to have a little section on the site to see some great things made with SFML.