Don't worry, you won't be that 64k guy. 64 bit gives the possibility of 2^64 bytes of addressable memory. That's over 18 exabytes. The entire digital content of the web is only estimated at about 90 petabytes.

If we go to 2^128 or 2^256, we start moving into numbers really large numbers. I and I really large. The number of atoms in our galaxy in near 2^220.