I've got Giardelli's mix here right now, and it's pretty good. (You need real milk for it - none of that powdered stuff included.) I also have a box of Droste cocoa, which makes wonderful hot chocolate. A trick straight off a previous box, purchased in Holland, is to add a little bit of butter on the top.

The best stuff I've had was the Mexican hot chocolate. I think I bought that when I was in Indiana. It comes in solid blocks which you heat up slowly in about a quart of milk. I never got the entire chunk to disolve completely, but it was sort of fun to find a lump of concentrated flavor down at the bottom. Amazing taste! (And yes, it included cinnamon and other spices.)