Edward Tufte would have a field day with these. They may be a useful visual reminder of whether a megabyte is larger or smaller than a gigabyte (should anyone geeky enough to have some of these actually need a reminder) but in no respect are any of these proportional in size to each other in a way that reflects the scaling of their names.

That's probably a good thing, in practical terms, though. I hate to think just how large the "terabyte" would be, even scaled by volume, to get it to match the "bit".

Original idea and production: http://www.artlebedev.ru/everything/matryoshkus/