It seems like Armory and Bitcoin Core are taking up 78GB so far, and it's not even done downloading. How much more space will I need? Is it possible to get rid of some of the data after it is all done? So far the Building Databases step has taken up the most GB. I'm using it on Ubuntu.
In total, it's about 61GB for me right now. In general, it should be about twice the size of the blockchain (which is always growing).
There can be some intermediate files (e.g. bootstrap.dat, 21GB currently; or Armory's similar torrent) involved that increase how much space you need during initial setup.
These can be deleted when you're done using them. (In the case of bootstrap.dat, that's when Bitcoin Core finishes loading data from disk; it's not deleted automatically, you'd delete it manually.)