Searching for this particular question didn't yield many results, here's another, older thread too: Option to use Correct SI Binary Prefixes for Quantities
So, although this is an old thing bumped, I'd personally like to see an option to view the sizes with the correct notation, even though I realise it is basically cosmetic.
You could have an option to view them in actual base 10 sizes too, because bear in mind Mac OS X now does this since Snow Leopard - it does NOT report sizes we all think of, it uses the sizes hard drive manufacturers have all been using.
So, as much as people think it doesn't matter, there is real confusion to be had, especially when using both Operating Systems.
I'd like to see an option to calculate it as Mac OS X does, (although I personally wouldn't use that), a way to calculate it as currently done, but with the correct notation (KiB, MiB, GiB, TiB.. etc) and a way to use the calculation we're used to, but with the old, incorrect notation. The last probably being the default to reduce complaints. I'd personally use the second option. I just prefer it to look right, I suppose.