Video walkthroughs are always good so people can see how to get past a place they're stuck in (because just reading something isn't always enough). Videos of boss battles or dissidia player matches could be good as well.

AMVs would be awesome even though FF doesn't necessarily have much to work with in that department (FF7 movies, FF Unlimited, and maybe the other FF movies.)

Cosplay skits could be awesome as well as you could do a wide range of genres from humor, to emotional, to a long TV episode -ish type thing.