The whole concept of 64bit computers for desktop users is in very much in the news at the moment. We have from AMD the 64 and from Apple the G5 (although the processor itself was jointly developed with IBM). We have had 64bit processors for servers (for example Intel's Itanium), but it is only now that processors aimed at desktop machines have become available.

The benefits of 64bit processors are numerous. They can address far more memory than 32bit processors (which are limited to 4GB). The whole architecture can cope with far more data throughput. The main problem is that to take advantage of the extra speed 32bit applications need to be optimised. The AMD64 can run 32bit applications, but to take full advantage you really need to be running 64bit application.

The G5 can also run 32bit applications. However, the advantage that the G5 has, is that its instruction set was designed for the shift from 32bit to 64bit. However, with some optimisation applications can still be made to run faster. It is notable that the many 64bit applications are already out for the G5 such as Mac OSX and also most of the Adobe programs.

If you really want 64bit computing today, but do not really want to switch to Macs, you could buy an AMD64. However, it might be more prudent to wait for the 64bit applications. By that time, the price of 64bit computing will have come down in price.