My preference is unsweetened cocoa powder, which may not really be chocolate, I've never been sure
It depends if you consider chocolate to be the finished product or the processed beans, but it's a sliding scale. You can get 99% chocolate that has no extra sugar or milk and it's still recognisable as chocolate.
You sound like you know all this, but the processed beans produce "cocoa mass" which is made up of two components;
- Cocoa butter (a pale yellow fat with little flavour)
- Cocoa solids (a dark, strong powder, pretty much what you buy as cocoa powder)
White chocolate is only the butter with a bunch of milk, sugar and flavourings, and is often said to not be real chocolate because it doesn't contain solids. This is where I remain unsure also - is the determining factor the presence of solids, or the presence of both solids and butter? Personally I am happy to call it all chocolate.