Upgrade to 64-bit?
 

I have a dubious motherboard and CPU. Is this a good time to upgrade to an Athlon 64 and 754-pin motherboard? I have some PC2700 memory on the way. Are drivers for common hardward (HP printers, Iomega CD burners, etc.) available? I'm using Fedora 1; I think maybe there's a 64-bit version of 2 or 3? It's upgrade now or wait 2-3 years.

All native Linux drivers magically work on all supported platforms, including x86_64. Some closed-source drivers (or programs) will have to work in 32-bit compatibility mode but apart from that there's no reason not to upgrade for the sake of software.

EDIT: The AMD Operon, unlike the IBM chips, processes 32-bit code not much slower than a 32-bit processor.

If you wait 2 or 3 years, I predict that currently available hardware will be cheaper or obsoleted, and faster/more powerful hardware will be available.

The big advantages of a 64-bit processor over the same speed of 32-bit CPU are a faster access to a large address space (for accessing large RAM or hard disk phisical/logical partitions), and faster processing of 64-bit numbers for real number-crunching applications.