I _strongly_ warn against using FreeBSD. We tried it for a few months and it regularly kicked our ass until we switched back to RH6.2. AOLserver simply is not well supported on that platform yet.
Perhaps we did something wrong, but everything we did do never worked. It got to the point where we were rebooting our servers 2 or 3 times a day because of memory leaks and hung processes.
If you can figure out a way to get it to work or can submit a patch, booya. We'd love to be able to use a *BSD for no other reason than greater familiarity.
But as Don said, what works is best. Strip out all the default security holes in RH 6.2 and you can feel secure your system will run.
tal