How popular is Blu-Ray these days?

My girlfriend wants to build a computer from scratch. I’m pretty knowledgeable in most areas of computer building having built several of my own, one last year. When I looked at Blu-Ray drives before, they were pretty expensive and just didn’t seem worth the extra money. Today though, I walk into Best Buy or Target or any other retailer and see Blu-Ray movies everywhere. My girlfriend @carly mentioned she’d like to include a Blu-Ray drive with her new computer – is Blu-Ray really the wave of the future?