Sorry, BD-R may not be expensive in the USA, but it certainly is in Brazil. VERY EXPENSIVE!
And it would also mean buying a BD-R burner/reader, which is quite expensive too. I think it's not a technology for me.
The more I think about it, the more I see my only future is a video server. Even in SSD, which will soon be affordable in 4TB, would pay off when you add up BD-R media.