I am starting a small web hosting company overseas and I am trying to decide what hardware/software to use. The setup needs to be able to support HTTP, FTP, PHP, MySQL, and mail. This is what I am thinking:

I can afford to build 3 x 1U Rackmount machines
Athlon 64 X2 3800+
2GB DDR400 ECC Ram
Tyan Server Board
2 X SATAII 160GB Drives hardware mirrored

Am I better off building these machines and running them in a cluster or one better dual processor machine?

My only experience is with Ubuntu but I just got Fedora Core 4. I am thinking about using that and Ultramonkey for load balancing (I am still a little foggy on the load balancing / LVS software setup)

I am looking at cpanel or h-sphere for the end user control panel. Is there a (free) open source solution for this?

So I guess the main questions are cluster vs. single machine, which distro and which other software.