I'd like to avoid Miami or Boston. While I think the 76ers would get past either one, those would be the teams most likely to take a toll on the 76ers in terms of emotion, effort, games it would take, etc. It's not hard for me to see either a Philly-Miami or Philly-Boston series go 7 games.
Atlanta, Charlotte, Indiana, or Washington shouldn't take the 76ers past 5 games in my opinion.