Well if you train in Hungary you have arrived once you get to black belt. (As far as Im concerned anyway.) These guys are hardcore by the time the belt roles around, at least the guys I have seen.
The point is this varies around the world...I have read in Japan it is the starting point...seems black belt isnt that serious.
Point is, but then you know Aikido and can move around fluently, improvise, and combine it with normal atemi attacks...whether it be kicks, etc. - if you cant, then at black belt, your can say your at the beginning.
Either way, I will congratulate you, as your further by far it would appear then myself who am not even in the shadow of the black belt yet.
Seriously, congrats on this, I bet you are excited.
As far as what you should do once you get it, nothing different than now. If you are into Aikido, your into it, and black or not wont change it that much...what will change is when you reach the point where you can easily convey why it is the techniques do what they do and you become a teacher.
So black belt, in my humble opinion, is time to start transmitting what you know. (But in honesty, I think that starts at any level, though at a more proficient level, of course, by the time you reach the level I mentioned earlier.)