The offline maps like Osmand and whatnot elide a bunch of data and include indexes, and last I did the arithmetic, were in the vicinity of 50 GB. Numbers here:
Agree, that's uncompressed and with all of the required scaffolding. I would still argue that in the next few years, you'll be able to carry an entirely functional OSM system around with you, tile cache and all (Samsung is predicting 128TB SSDs by 2018).
