I always thought that instant hot chocolate had powdered milk in it, so there was no need to add milk, just water to reconstitute what was already in it.

Land O'Lakes used to make flavored instant hot chocolate (or maybe still makes -- I can't remember seeing them recently, though). The raspberry flavored one (which I made with water) was soooooo good, and I don't even like raspberries that much.

Another fun thing to do with instant hot chocolate is add those flavored coffee creamers to them. Amaretto flavor is great, so is irish cream.