Chris Pirillo's been making a ton of noise over a video he posted showing off a YouTube video of a demo of the XGL desktop running on KDE.
He then turns around and asks "Why can't Vista look like this?". I'm not a UX (user experience) guy, but I have watched the video and I've got some pretty strong opinions about it.
First off, he's right - this is a pretty amazing demo. It has TONS of eye candy. The "bouncy" effects on the windows are very pretty. The rotating cube is cool, as is the "windows bump into each other" effect. Having said all that, there's a TON of distance between a cool demo (or proof of concept, or whatever it is you call something that's not shipping in a product for millions of consumers).
For instance, the bouncy windows make you seasick after a while. And the cube desktop, while slick has some serious issues - for instance, you've got a strong potential for "losing" your windows (because they're on a face of the cube that's obscured).
The key thing to realize is that it's relatively easy to make a cool UI. I've seen the most amazing proof of concepts for Windows UI coming from our advanced UX team. Really compelling stuff, that just knocks your socks off.
And not one of them has ever seen the light of day outside of Microsoft (to my knowledge).
Why is this? Because making a good user experience is HARD. It's easy to make a cool user experience, it's REALLY hard to make one that's good, and that works for millions of users. There are a ton of things you need to consider. You need to consider usability, accessibility, localizability (yeah, it matters - Right-To-Left languages may have differnt visual conventions than Left-To-Right languages), all sorts of other *bilities. I've been through enough and read enough UX reviews over the redesigned multimedia control panel in Vista to realize the complexity of the things that these guys have to deal with. It's a lot harder than you think. John Gruber over at Daring FIreball has a classic post entitled "Ronco Spray-On Usability where he talks about some of hte issues.
Take floppy windows for example. The Shell Fit&Finish dude (Dave Vroney) just put out a post explaining why they disabled floppy windows. The answer is that they significantly reduce the usability of the system. They may be cool but they get really annoying really soon.
And, of course, Vista is only V1 of the DWM. This release is about getting the heavy lifting and building a new desktop compositing engine. Future releases are likely to have a ton more cool stuff coming from the UI wizards now that they have a platform on which they can do really cool things.