Plug in an external BD device. Playback is not native (yet) and requires a third party player. Content composition can be handled by iMovie (or Finalcut). Burning to BD requires a 3rd party app. There's been speculation of BD in the 2012 iMac lineup, but there's also been equal speculation that Apple is going to do-away with optical disks in favor of net-streaming. As a technologist, I understand that we are nearing the end of the age of optical-disks being a contemporary distribution medium. I just don't know if we're all ready for it yet. Even on my old 1080p Panasonic plasma, I can see the quality difference between BD and streamed media. My guess is that BD will die the moment someone figures out how to get comparable quality at an acceptable bitrate.
On the photo side, I was able to accomplish more with iPhoto in two days than I did with Picasa in 4 years. The difference was that I didn't have to learn to do anything, I simply did it. There was nothing to figure out. While I do not foresee myself ever needing Photoshop, I did install Apeture, which helped me give life to some of scans from the huge-box-of-pictures that my mother had in her attic. Speaking of which, I found a charming one of myself at age 2 in just a diaper and batman-mask. Some things never change.
iWork is great for those that do not require a full-on Office suite. It's targeted at the same users that MS tried to target with their MS-Works crapware. Think of it as K-Office, or whatever is called now. If you require a full office suite, you can take your pick (MS-Office, Libreoffice, etc all run fine). Try to understand that MS has brainwashed you into thinking you need a full-featured Office suite at home and for school. You probably don't. You definitely don't need one to make bake-sale fliers, resumes, brochures, compose written academic work, etc. Full featured office suites often give me worse results than a lesser suite with a better workflow and templates. If I look at a couple of the projects I have composed with Pages, I would be hard-pressed to find a way to produce the same quality in Word/Writer.
All in all, it's really no better or worse than PC. It's just different. It's simple. How to do things is often obvious and isn't buried in a ribbon or tiny black arrow in the corner of a grey box with some indecipherable picture on it. I spend less time figuring out how to do something (and often learning the wrong way) and more time doing actual work.