I think I can add a little more. For the purpose of chocolate chip cookies, we'll refer to the pre-formed chips in bags (or bulk, if you can buy them that way).
Under US regulations, "milk chocolate" needs to contain a certain amount of milk. It contains less cocoa (what makes chocolate "chocolate") and a generous amount of sugar. "Dark chocolate" contains no milk, or perhaps a trace but still too little to label "milk", and a higher concentration of cocoa, less sugar. "Semi-sweet" is the in-between. No milk, less cocoa than "dark", and more sugar, too. You are right about US milk chocolate being inferior to the European made, rr
As far as "bittersweet" and the rest, those are usually blocks of chocolate that can be broken or grated into a recipe, mostly to melt and incorporate into the moist base of a recipe. "Unsweetened" is just that - no sugar added. Dry and bitter. Eat a piece once, you'll never forget.
As far as which chips to use in your cookie, giovannadia
, you can use any kind you would like. When I make chocolate chip cookies, I prefer the dark chocolate chips. They are less sweet and more chocolate intense than my other choices. Go big-flavored, I say.
Hope this helps. (Hope I'm right.