Which FC for a Dell poweredge server?

I'm in the process of ordering a new server box - a Dell Poweredge -
and wondered if anyone could offer quick advice on which FC version I
should download and install?

I'm asking in relation to compatabilty with the likely hardware etc,
for example:

Intel E7230 chipset
SATA HDD
Intel D820 2.8GHz
512MB DDR2 SDRAM

I'm thinking about FC4 but as this is a development/test server the
primary objective is that anything running on this MUST also run on
the live server installed with RH3 ES-13.8.3

I will of course ensure that the versions of PHP and MySQL etc match
the live server.

Any help or advice much appreciated.

--
Graham