The whole 32bit vs 64bit argument has been going around for quite some time. Most people probably won't see a difference between a 32bit and 64bit environment as most programs just doen't need the wider 64bit registers yet.
As for the memory support it is not that big a deal. A 64bit OS can directly address more than 4G RAM, but even for this there is a solution at least for Linux with HIGHMEM64G.
Large memory support is not the only thing a 64bit OS is good for. If you do video processing, work with large databases, or large file manipulation/transfers (greater than 4Gb), then a 64bit OS might be for you.
However, currently there is better codec support on 32bit OSes currently for multimedia. Although with Sabayon I rarely come across media that doesn't play. The only real issues I have are the new vids that use WMA9.
If you check the wiki, use the search function and google you can find the answer to most of your questions.
Remember to mark your thread [Solved] if your issue is fixed.