I used to have a physical ESX server running ESX or ESXi (from USB) but due to the problems of running DRS, HA and VMotion with only one ESX server I switched to a full blown virtual environment.

A Quad Core i7 with 6 GB of ram running Windows 7.

If you are wondering of why I installed Windows 7 instead of ESX, the answer is quite simple.
I’m running all my ESX 4.x servers, vCenter server, EDA and Openfiler inside VMware Workstation 7 beta.
Yes, thats right. Workstation 7 runs ESX out of the box. And I’m even able to run VM inside my ESX 4.x hosts.

So my setup looks like this:

• A EDA appliance (as ow writing version 0.90)
• A vCenter server running on Windows 2008 and MSSQL2005
• Two ESX 4.x hosts (2vCPU and 2 GB ram)
  Deployed through the EDA appliance. Easy as hell to setup.
• A Openfiler appliance for iSCSI shared storage

Nothing fancy, but it works and is simple.