Blu-ray Disc (or BD) players were first launched in June 2006 as an alternative to HD (High Definition) DVD players. Later that year Sony included Blu-ray technology in its new PlayStation 3 players and since then have sold over 10 million. In February 2008, HD DVD maker Toshiba announced "game over" to HD DVD. And thus Blu-ray has become the high-def format of choice.
This was Sony's revenge I suppose for the Betamax format losing out to JVC's VHS video recording format in the mid 1980s. For the million or so HD DVD purchasers, you were brave! But good luck finding DVDs in this now obsolete format.
What is Blu-ray? Blu-ray is a high-definition technology that uses a blue laser to read the disc (DVD players use a red laser). Blu-ray screen resolution is 1,080 horizontal lines versus 480 for DVDs. That added resolution can make for a stunning picture. But you need a high-def TV to enjoy it! BDs have 6 times the storage capacity of DVDs.
Will BD make DVD go obsolete soon? My personal opinion is no, given the fact that hundreds of millions of DVD players are in use and continue being sold. But BD will gradually creep into the DVD market. I would imagine that BDs will grow in popularity at similar rate to the growth in high-definition TVs vs analog TVs.
Should I buy one? If you own a PlayStation 3, perhaps use that to play BDs until BD player prices start falling from their current $400 price tag. Heck you can buy a PS3 for $400 today. But if you enjoy being an early adopter and don't mind the fact the prices may drop towards Christmas, go for it! One thing to make sure though is that your BD player is "backwards compatible" with DVDs. Most are but make sure to check.
Blu-ray Discs also cost slightly more to rent today, but not that much more. A local Newbury Park Blockbuster rents BDs for about $1 more than DVDs.