64-bit processors and operating systems will become a lot more relevant for most users as the amount of RAM in computers increases. At the current rate of things, it won't be long before 4GB of RAM or more becomes standard in most new computers.

As a side note, you don't necessarily need a 64-bit CPU to use over 4GB of RAM. If you have an operating system such as Linux<sup>*</sup> or Vista SP1 you can use more than 4GB of RAM through physical address extension.

* You might have to compile PAE support into your Linux kernel. I don't know as I haven't personally tried setting up such a system.