I have 1 & 2 on SD and won't buy the BLUs. I would if it was a show where you could just watch one episode here and there like Seinfeld, Frasier, whatever.
I AM buying Lost 3 on BLU though. Can't wait.
I have Prison Break 1 & 2 on SD. It would be nice if the studios would release seasons on BLU when the SDs come out, because I'm not waiting.