You may be better served to find a mothboard that works with ESX that has 4x4GB capability rather than 2x4GB memory max. Memory is commonly the limiting factor in the number of VMs you can get on an ESX host.
Also, I noticed the audio on that motherboard is Realtek and if the NIC is also Realtek then the motherboard NIC is not likely to work with ESX -- you'd need some addin gigabit NIC cards such as a dual or quad PCI-e NIC Intel card for that 16X PCI-e slot (requires at least 4X PCI-e slot for the dual and quad gigabit Intel NICs) and/or some regular PCI NICs such as Intel 1000MT PCI NICs. If possible, you'll want at least four physical NICs (more if you're intending to do VMware FT) -- 1 NIC for Service Console Active and VMotion Standby, 1 NIC for Service Console Standby and VMotion Active and 2 NICs for VM traffic. If you're going to implement VMware FT, I wouldn't put the FT Logging traffic on any of the first four NICs -- VMware FT creates quite a bit of traffic so it would be best to put VMware FT Logging on a separate 5th NIC.
Also, it's highly unlikely that a motherboard driver-based (not hardware) RAID controller is going
to be understood by ESX -- if you must have RAID on the local disks
you'll likely need a separate add-in RAID controller that is on the HCL or known to work with ESX 4.0.
As you can see, what someone else suggested about getting a server from HP, IBM or Dell may make financial sense when you start looking at all the addins and memory quantity.
For others who may be looking at a very low cost AMD white box lab that can do VMware FT, you can find details and caveats of part of my home lab here:
http://communities.vmware.com/thread/218140
Datto
.