Michelle in 2016!
All joking aside, I think both Clinton and Obama broke down the barriers that may have prevented a greater number of women and minorities from running at all. I don't think we'll ever see another election in which all the candidates are white males. I think that having another black president in the next 50-60 years is going to depend largely on the quality of the black candidates who choose to run.
The greater impact of Obama's landmark victory is going to be felt down ballot. I think you will start seeing more minority governors and Senators as well as more minority representatives from majority white districts.