Reasonable Hardware For Home VM Experimentation?

You can easily get dual (possibly quad?)-cpu AMD mobo's and add to the power. It's the server line you'd use but same basic technology. $500 USD would get you a single Phenom 940 with 8GB of ECC ram, computers are cheap these days.

There's a suggestion (marked 'funny') of a MacPro. I confess that last week I window-shopped, at the Apple store, an 8-core Xeon with 16GB RAM for about 3500 euros (single HD).

However, a whitebox PhenomII 940 quadcore with 8GB ECC RAM will run under 600 euros. That's probably about half the muscle, good enough to start (and cover a lot of road ...). Toss in a 600 euro MacMini if/when MacOS is wanted.