When, if ever will blu ray drives become standard.

[Alby_da_Wolf]

@OP
BD read-only has a reduced usefulness on PC's, so I'll consider BD-R/RE
If BD-R drives get fast under $100 their mass adoption as RW optical units on PC's can begin, to become the standard they must get even cheaper.
The first stage of adoption, mass, but still minority compared to DVD-R, when price falls under $100, can begin even before 2012, late 2010 given the current price, but then another two years, roughly, will have to pass before they drop under $50 and become commodities, so for that your 2012 estimate looks quite correct to me.
@BengaBenga:
I agree about movies: as even the biggest PC monitors are smaller than big TV's and best used close, while watching a movie is a typical relaxing activity that's more relaxing not staying too close to the screen, I don't see their main use on PC's for watching movies, more for storage and games.
As for flash cards, their price per GB is higher than BD discs' one, they'll be more used for faster on-the-fly copies and non permanent ones, also because rewritable discs are usually slower and more expensive than write-once ones, while write-once discs will be used for cheap permanent copies.