Brandon Isleib over at The Hardball Times has written a series of articles about what if there had always been two divisions in baseball since 1901. He has done a lot of research and put together on how the divisional play would've affected baseball from 1901 to 1968.

There are three articles and this article begins with links to the first two articles. It is interesting to see how some teams with divisional play may have gotten into the playoffs and how others went from just appearing into a dominance in their division. I found it to be a lot of fun to read, especially during the off-season when I am bored because there is no baseball.
Hope you find these articles as interesting as I did.