CoolDude has covered a lot of the important points.
I've been using a Mac front-end to control my media playback, and have described this here when I began doing so in 2007. Afterwards, a number of very sophisticated solutions for integration have been suggested by other members. Since there are so many possible avenues/approachoes/solutions, I think it's probably useful to describe some overall goals with an installation.
1. Very important to me was having simple control of content, in my hand, with a two-way remote that let me select sources. That was solved with iPod Touch and iPhone, and will be similarly simple with the iPad, though maybe not as portable as the two other units. But I will still like having the larger control surface, and am in fact using a MacBook today to control my Mac mini, which is the core of my setup.
2. Storage capacity. This is easily solved with storage devices such as those from ReadyNAS, they can be easily connected to a network and controlled through a Mac media centre. I have 4TB of storage space, and won't have filled it up anytime soon.
3. Simple control of peripherals and storage.
This is where the iPad will really come into its own. The larger screen will allow for better feedback. Today, I'm using the MacBook for this, but it's not as elegant solution as what will be possible using an iPad. Screen sharing on the MacBook gives me a replica of the Mac mini desktop on the MacBook screen, and I can then do all kinds of control and administration tasks through that (organizing sources, maintenance of server, etc.)
It's very simple, but not entirely push&play -- so maybe there's room here for the kind of integration that Linkplayer affords, in order to ease the user experience.
4. Porting HD audio and video from the media centre to the B&O speakers and screens.
Let's face it - B&O have not been able to create satisfactory media centre solutions, and events have not only overtaken B&O in this respect, they're left in the dust, with inferior offerings. Maybe new mgt will fix this. In 2005 I was told to "pack your Mac, go back" when I showed top mgt what was in the pipeline from Apple, and what this would mean for A/V-companies.
So we're left with having to create workarounds in order to get the best possible A/V experience from the excellent B&O screens and speakers. But getting HD audio from a Mac mini or similar is no problem at all, and you can even get it in various resolutions. It's rumored that Apple will offer "auto-detection" of resolutions, meaning we'll no longer have to go into Audio MIDI Setup (utility) in order to change these - my DAC which is connected to my BL5s autodetects resolutions, but this is an area where work can be done.
I have absolutely excellent images from ATV when I watch HD-movies, looks simply brilliant. Audio is not as good as top resolution audio from a Blu-ray disc, since the 5-channel from ATV is not high-resolution. So this is an area where we'll have to hope that higher resolutions will be offered for download.
Setting up for porting from a Mac to speakers and screens is simple - though I've found I have to use non-B&O intermediate devices to get the best quality.
5. I'm using Ethernet and Wireless for transfer of content. Wireless works excellently, even for high-resolution content and with various users using the same net at the same time - but I find that having ethernet from the room the server is in (they can be noisy) to the Mac mini has completely (totally and absolutely) eliminated any drop-outs during playback.
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In the future, I'll be using an iPad for main-room control and admin, but I will continue using iPod Touch and iPhone for general control of playback in other rooms. The remote in these controls both iTunes on the Mac mini and the ATV, and I can stream content with ease.
The content sharing functions built into iTunes also make it easy to stream video at high quality, using the wireless that Apple offers.