Some nice comments on what I wrote.

First, a non-controversial question. Robin asked whether you would capitalize them in that case, and I think you should, as having something accessed externally that isn't properly cased will be surprising to people.

Dani - and others - have pointed out that properties leave your options open in case the software is used in ways that make the property more useful. This is certainly true, and I think it comes down to how you value that flexibility over the tax that you're paying to have properties. I would usually rate the simplicity higher, but it does depend on what you're writing, how likely the code is to get repurposed, and how likely it is that a property would ever be needed. I find as I get older I'm valuing simplicity more.

Finally, Kristof points out that a field can be passed as an out or ref parameter while a property cannot, which means that adding a property to code can break the client code. This is a good point. I do think, however, that I'd want my code to break in that situation - if something is a property I should do some thinking about whether it's a good idea to be passing it as an out or ref (the same reason C# doesn't write helper code to make this work by default).

Kristof's comment reminded me one more reason to use properties - some of the BCL infrastructure works with properties but not with fields.