[soko]

64bit is not revolutionary like 32bit processing was, therefore it will take much longer for the home computing market to transition to it (low demand) and there will be support for 32bit processors for at least a few decades to come.

For cool points you might consider it but if you don't know why you would need a 64bit system then you don't need one.

4GB of ram is a lot, even if you can't tap in to all of it and want to make it available the chances you actually use it are slim.

Gaming is maybe the only thing that could benefit, if you like to watch DVD movies and edit vector images while you encode DIVX movies and serve and FTP while playing Bioshock online.