I could care less about Prision Break, and already own al 24 series releases. Although I will replace most movies with the HD versions when they become available, TV series are another matter. New seasons I will buy in HD, old seasons I will not replace.
Especially the shows like 24, where once you know the twists and turns it's not as watchable the second time. Buffy, Angel, Lost, maybe. Firefly? Definitely. 24, Prison Break? Doubtfull. I'll just pick up with HD versions as the new seasons are released.