Sim 3 for PC is my favorite as well. I haven't played it in a little while, but my favorite thing to do was exercise my creativity wherever I could. I know Sims 4 allows that exceptionally well, but I also love the full scope of what Sims 3 offers. It is definitely the most expansive game of the series.
My only wish is that EA would stop using it as a money-grabbing platform. That is the one thing ruining the Sims games.