I like a system whereby individuals can own between one and a bit and three somewhere (including provision for commercial property where large facilities need to rent many people's fungible extra-property rights in some way). Mentioning 100% tax is just to head off idiotic straw men about passing the tax on to renters.

Also allowing benefiting from or even rent seeking on only the increased value of very recent property improvements (like taxing at the value it held 5 years ago with some buy-or-sell challenge type provision to prevent undervaluing).