[CentOS] Desktop/Server 32/64 (was Re: Silly question x64 vs i386)

I have one box on my home network that is x86_64 capable... My other boxes are all i386. As this x86_64 machine can, at most, house 4 GB of RAM (currently only has 1 GB) - is there any advantage to my running x86_64 on that machine instead of i386... Long story as to why I am asking - but before I go off and moveit down to i386 - just wanted some opinions :)

If I may hijack, what about desktop machines? Would your 32/64 choice be the same if it were primarily a desktop machine vs. primarily a server? I recall a year or so ago the answer was 32 bit for desktops, but perhaps that has changed.