migrate server on freebsd amd64

[Valentin Bud]

Hello list,
 I want your opinion about migrating a freebsd server to amd64.
I have the following configuration:

Motherboard: Intel S5000VSA
CPU: Intel Xeon E5335 @ 2Ghz
RAM: 2 x 1Gb DDR2 FB-DIMM 667Mhz
HDD: 2 x 320 Gb SATA II + 1 x 500 Gb SATA II

This server runs as a web / mail server using:
Apache 2.2
MySQL 5.0
php 5
Imagick
ghostscript
postfix + dovecot
openvpn

Currently the server runs FBSD 7.0 i386 (RELENG_7). I plan to switch the
server to amd64
and use ZFS.
I want your suggestions about the above applications and their stability on
64 bit FBSD as well
as suggestions about running ZFS on the given hardware. I will upgrade the
RAM in the near future to
4 Gb. The CPU is out of the question because of the cost.

 I'm sorry if this is not the proper place to ask questions about FBSD amd64
but i thought that here are many
people that might be using amd64 and come with some opinions. Thank you.

all the best,
v