It all depends on your preferences. I like my Tokaido cotton 1-1/2 " belt, but then again I don't like a really wide belt.
Shureido makes a good belt too.
Chances are, however, unless your instructor asked you what belt you would like to receive if you pass your black belt test, he probably already has a supplier and will provide you with the best that he knows about.
In that case, I would be elated that you receive one at all and wear what he presents you.