Ever since I was a young kid, I was confused by how sometimes, a megabyte was 1000000 bytes and sometimes something different. This confusion still gets me to this day, and it's because there's no consistency.
The webcomic xkcd has a great take on it regarding the smaller unit kilobyte. For the unit "megabyte", the problem is compounded by the extra multiplication possibility: megabyte can not only be either 1000^2 or 1024^2 bytes, but it can also be 1024*1000 bytes.
Yesterday, that issue came back to bite me. I was creating a new partition on my flash drive to make a Linux Mint 10 "Julia" GNOME live USB system. The ISO file is under 850 MB (whatever "MB" means), so I created a partition that's 900 MiB (a MiB is bigger than an MB, as far as I know) to be safe. I started UnetBootin and started writing the ISO to the partition, then got an error saying the partition has run out of room.
Now, it may be entirely possible that an ISO file takes up a lot more room when written to a USB stick partition as opposed to a CD/DVD, though I'd be surprised if it took up that much more room. But I have a feeling it's because of the inconsistent use of MB in GParted vs. Nautilus. Come on, can we please have some consistency?