Hi
The entire computing industry is moving from 32-bit to 64-bit technology. Today’s Macs can hold up to 32GB of physical memory, but the 32-bit applications that run on them can address only 4GB of RAM at a time. 64-bit computing enables applications to address a theoretical 16 billion gigabytes of memory, or 16 exabytes. It can also enable computers to crunch twice the data per clock cycle, which can dramatically speed up numeric calculations and other tasks. Earlier versions of Mac OS X have offered a range of 64-bit capabilities.
Nearly all system applications — including the Finder, Mail, Safari, iCal, and iChat — are now built with 64-bit code. So not only are they able to take full advantage of all the memory in your Mac, but the move to 64-bit applications also boosts overall performance. Together with other refinements and improvements in Snow Leopard, this means that just about everything you do — from launching applications like QuickTime to running JavaScript in Safari to opening image files — will feel faster and more responsive.
So as you said, you aren't doing any programming or designing ludicrous graphics, but your Mac would still be better off running in 64-bit mode. Is your reason for wanting to run in 32-bit mode simply to be able to use the BlackBerry Desktop Manager for Mac? It should still working when running in 64-bit, but you could look at using
Boot Camp perhaps to run it in Windows.
Hope this helps 🙂
Taylor