Fun fact: the AS/400 virtual instruction set uses 128-bit pointers (that get truncated when executing on a real machine). It's not excessive considering that the AS/400 is not only a flat-memory architecture, but a single-level store.

I think storage will eventually move to the Venti model of hash addressing. It just makes much more sense on a network and with current archive-everything practices (there are some really big wins to be gained from compression and dedup there). BitTorrent is doing this already.