I do not go actively looking for spoilers but I'd be happy to hear both the good and the bad so that I can prepare myself for disappointment.

The 100th episode is the royal wedding. There have been lots of photos of Blair in her wedding dress, on the street and looking upset, apparently having run out of the reception. And there's supposed to be a scene at JFK airport with Dan and Blair, both in their wedding attire, which is probably in that episode also. But Louis is still around in episode 14, so there's no end to the royal crap in sight.