I personally prefer base 2 units for file size.  A 2GB file will take 2GB of memory when I load it in.  Hard drive page sizes are also base two, 512 bytes for most drives and 4096 bytes (4K) for newer large capacity drives.<p>I also prefer base 2 for file transfer speeds just so it matches the file size convention.  Fortunately most programs either default to base 2 or let you chose in the preferences.<p>Network line speeds are in base 10 (100Mbit ethernet is actually 100,000,000 bits&#x2F;s) but there so much protocol overhead and other factors that comparing transfer speeds and line speeds is moot in most situations.