The Bar? I was recently thinking about it and was pondering how the series would be if Sam decided to go with Diane and embark on a journey with her instead of going back to the familiarity of the bar and his friends. How would things be different? How would Sam's friends react? Although I enjoy the finale it had , I am curious as to what would have happened if Sam didn't go back to the bar.

Easy answer - the show would have ended at that point (the end of S05). I don't see the series continuing without Sam. Though the Diane character was disposable (and the series improved after she left) Sam was the lifeblood of the show.