Pervasive is one of my favourites, I'm trying to fine tune my grammar at the moment so learning how to use 'whilst' as apparantly that's better than some alternatives. Also I've been told to use 'this' less.
i've found plethora, dearth, and paucity are good ways of saying 'there's a lot of' or 'there's not a lot of' whilst making it sound more intelligent and academic!