The key is going to be Storage first, then RAM. As long as hardware uses the same CPU's, that isn't a big deal. I personally have built hundreds to thousands of ESX hosts in the datacenter, both large and small deployments. At home, you just need a simple platform, I use the Dell 440, and for storage you can use iSCSI with OpenFiler. While I wouldn't recommend iSCSI for production/enterprise, it is great for small scale stuff.

Simply put, two new cheap servers identically configured, with at least 4-8GB RAM each (really this depends upon how much you want to use--the sky is the limit), and one system to run iSCSI / OpenFiler (can be different / older / repurposed hardware). Make sure to have enough NICS to isolate your iSCSI traffic to its own interface. TCO will probably be around ~$2000, if you have some old hardware laying around to fill in the gaps.

I don't see a way to edit, gah.

I have consolidated a large installation into 120 Physical servers, running over 600 Virtual Machines (a mix of Linux, Windows and even Sol x86).

I recommend that you need to seriously consider why you are doing it. If you are doing it for hardware savings, you have totally missed the concept of virtualization, which is savings through abstraction. If your site is so small that it can all fit on one server, perhaps virtualization is not for you. However, it still may be for you if you want the hardware availability features (the fact you can take a physical host down and keep everything running on the other, with ZERO downtime). These are the values of virtualization, and they are HUGE especially when you get into larger sites.

Now, Xen vs VMware... VMware does just work, and it is damn stable. And it is damn fast. If you have ever benchmarked VMware Server against Xen, throw your results away, go download ESXi (free) and try it again.

In my testing, with SPECint/fp results (we are an associate member of SPEC), AMD is around 5% overhead and Intel is around 10% overhead. With I/O, you run 10-15% FASTER in a VM than on the exact same physical system, period.