Dell 2850 use 32 or 64 bit?

[Tim Kellers]

I just bought a Dell 2850 (2 2.8GHZ dual core processors).  The server 
will be used as a webserver, e-mail server. and a db server (both 
PostgresQL and My SQL  Beyond the breaking of the 4 Gig RAM barrier, is 
there any compelling reason to use a 32 bit i386 or a 64 bit AMD OS?  
The machine currently has just a gig of RAM but I'm going to add more, 
soon.  The machine runs headless and has no xorg, installed.

A pointer to an article that discusses the 32 bit v 64 bit question 
would be appreciated as well.

dell# uname -a
FreeBSD dell.smsd.tv 7.1-PRERELEASE FreeBSD 7.1-PRERELEASE #0: Thu Dec 
25 04:12:57 EST 2008     root at dell.smsd.tv:/usr/obj/usr/src/sys/DELL  i386


TIA

Tim Kellers