But, Dan want you want to do is obscure - I work in a large IT department and no-one I know uses their PC to directly watch videos on their TV. Those that do download stuff and want to watch it on their nice big telly's generally do so by either streaming it via a media client, like a PS3 or XBOX, or by burning them to DVD. Probably because both solutions are fairly simple and far neater than having the PC / Laptop hooked up under the TV. Or even pointing a video camera at your monitor. And to be honest, until HD became common, the image on a TV was no match for even a fairly cheap monitor, which was actually the main disappointment for me when I tried it with the first card I bought that supported S-Video output.
IPlayer? You want to run a flash based stream up onto a big screen? As for the P2P version - surely the DRM still allows you to use a DLNA server to stream it to a media hub? It would certainly save you from having to fumble behind the TV and plug in the laptop in every time you forgot to record a programme?
The Dual monitor support seen in windows / mac was probably driven by two separate things - traveling reps wanting to use a projector or big screen to show those lovely powerpoint slide shows, and those MS Flight Sim enthusiasts from years ago who always wanted a triple monitor set-up(I used to be one of those).
So the card manufacturer's ensured the drivers they created for Microsoft and Apple systems had working multiple monitor support (after all its a function of the video card not the OS is it not?). I can imagine Apple and Microsoft were more than happy to extend their configuration applets to take advantage of this
Again, I see you backed away from trying to help persuade the card manufacturers to work with the community to ensure that good multiscreen driver support extends to X windows too? But thats the shill's base argument isn't it?. Theres no market for linux to do X, Y or Z, so why should manufacturers waste time working on it. If someone, such as yourself, who is happy to post such detailed comments on site such as this, claims they can't be bothered to feed their issues back up to people in the community and the manufacturers so it can be addressed and fixed properly, can you perhaps see why some of us would suspect your motives?. Especially when you then try to extend that to saying Linux is completely unfit for general desktop use as a result.
Here, I'll give you an example that I think is probably less of an obscure requirement than running a TV from a laptop, and probably more relevant to Joe Public. The SLI or Crossfire dual card setup, much coveted by hardcore gamers. If you buy such a system, yet find that it doesn't bring the claimed performance benefit and is often unstable, who do you blame? Microsoft? Or the card manufacturer for writing crap drivers? Who regularly gets slammed by the gaming community for this currently? Not Microsoft.
To say that Linux distro's should all say they are unfit for use by the Joe Public, just because trying to set up a slide show might take a little work is FUD. By the same token, I can bet most of the El Reg readership has seen a manager having to fumble around to get a presentation going on a windows laptop, so maybe Microsoft should also stop saying windows is fit for Joe Public by your standards. I'm sure my outfit doesn't have all the clueless PHB's in the world.
As I said, I've used Linux on the desktop for over 10 years, with probably less issues than I've had with windows over the same time.
As for Linux advertising that it doesn't support multi screen setup. I don't think I've ever seen it given as a reason to try linux. Similarly, I don't think I've come across any Windows advertising material that specifically highlights this feature. I might have seen it pushed as feature by a video card manufacturer, but then they always instruct you to install their drivers as soon as you fit the card, to allow you to access all wonderful features you shelled out for!
In real world terms I don't think the dual monitor support in linux, would be something Joe Public would have high on their list and I certainly don't think it comes close to all the issues being raised with Vista. And honestly, I don't think Joe Public cares, or is even aware of most the issues that cause people such as myself to move away from using Windows. I bet you'll have more joy, getting the the X-windows devs to look into sorting your multiple monitor support, than you will waiting for Microsoft to change it's spots.