I did install a FreeBSD 7.2 on IBM System x3650 in order to create a firewall to replace Checkpoint solution (which gives us more troubles than solution). The installation went flawlessly, so it won't be discussed here.
The firewall “script” is build with Firewall Builder and use Packet Filter from the OpenBSD project. OpenBSD was the first wanted system, but as it lacks support for IBM ServerRaid 8k, we had to switch to FreeBSD. NetBSD was also tested but link aggregation didn't work with Intel 82575 Gigabyte NIC.