2.) During the Buu arc, Vegeta had allowed himself to succumb to Babidi's magic in order to re-awaken the evil within his heart. Through his selfish actions, he resurrected Majin Buu. Although it didn't do much, I always enjoyed his final atonement.
To start off this thread, I'd like to point out a moment from the Android Arch. Vegeta had finally obtained his birthright, to become what he sought after for so long:
Sα΄α΄α΄Κ Sα΄ΙͺΚα΄Ι΄!
Contrary to what the vast majority of the 'fan base' believes. I think the new form. Beyond blue/Royal blue/ Blue Evolution. Was a well deserved form for the Prince. Who, since the beginning of Z has grown into the warrior we all know and love today.