Whether you buy or build your own make sure what ever you get is on the HCL http://www.vmware.com/resources/compatibility/search.php.
Personally I would by a name brand - that way you get a warranty
I would look at implementing VMware HA to protect yourself in the event of a host failure -
I'm moving my firewall and e-mail server to VMs under 1 host, such that it should act as if I did
the following:
HOST
<internet>---- [Firewall vm]---- <lan>
[ | ]
[ email vm ]
I'd have a DMZ within the HOST. And I'd need two NiCs for the HOST (vSphere). If I have a machine
with two NICs, would I be able to use one for the Internet and the other for the LAN?
Yes you would be able to do that by creating two virtual machine port groups = port group on the LAN and one on the Internet -