FFS PEOPLE.. God forbid someone wants to do something different to you. "why would you want to do that?"
That's the most stupid question I've seen asked here, much more stupid and fanboyish than the OP! What about; because the iMac has (generally) an incredible screen? and sitting inches away from it (like you do with computers, unlike TVs) BD on it would be a very compelling cinema experience.. And yes, you could easily tell the difference in quality, unless your vision is FUBAR, in which case why are you even paying a premium for a nicely designed/looking machine which you can barely see?

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Leave him alone, who wouldn't like BD in Macs? If you have a BD collection of COURSE you'd want to play it on your expensive, giant iMac too! Do you watch DVDs on your Macs sometimes? How is this different? The iMac can display 1080 easily, the video card is there.. I have a dual display iMac.. I'd LOVE bluray support.
If this is what makes a Wintroll to you, it makes me pretty ashamed. Apple can't claim to be ahead of the curve while ignoring "inconvenient" features.
Stop shooting the goddamn messenger, for most people BD is a hell of a lot more logical than ATV. Apple WILL support BD once the prices drop and slot loaded drives begin spreading, it isn't going away. I'm an Apple fan as much as any of you, but sometimes they don't give people what they want or need. They deserve questioning about this. It *must* become a BTO option, and soon. We're the media market, we need to be able to burn and *watch* these goddamn discs.
Surround wont be a problem anyway, even if you dont want to set up a digital optical connection you can always get a USB or firewire 5.1 surround box, which might save a little desk space. There are USb speakers with the surround interface built in too.
I'd be interested to see if Vista in Parallels or VMware would play BD in a virtual machine/from the bootcamp partition - that would be a killer feature. A stupid killer feature, as

should support it already anyway, but one nonetheless.
And watch for the jump in iMac sales, I'm pretty sure it'll be largely because of the ridiculous graphics cards in previous models. Look at all the threads here, the Mac community is lapping up the 8800, it should've been an option earlier, or something similar at least!