At number one, they place Mac OS X's Expose, and I must say, I fully agree. I can barely function without Apple's Expose, and navigating through windows in Microsoft's operating system has been cumbersome ever since I first used Expose. In Windows Vista, Microsoft was apparently afraid to simply blatantly copy Expose (what they should have done) and introduced Flip3D: the world's most useless compromise. I'm not particularly impressed with the implementation of Expose in Compiz either; no matter how much I tweak the various parameters, it never seems to function just as smooth and 'right' as Apple's Expose.
At number 4, PCWorld mentions Time Machine. Of course, the more expensive versions of Vista have everything in place to provide similar functionality, but the interface is cumbersome, and setting it up to backup to external disks is difficult. The cheaper versions of Vista require Shadow Explorer to access the shadow copies. Microsoft should get off its butt and make Volume Shadow Copy just as easy to use as Time Machine.
The article mentions other usual suspects such as Windows' lack of virtual desktops, lack of built-in .iso burning (cue ISO Recorder), sticky notes, and Compiz' desktop cube. A few others, however, are more interesting.
PCWorld thinks Windows should have a dock, just like Mac OS X. While they have a point in saying that Windows' start menu and taskbar are cumbersome, I wouldn't call the dock a much better idea, as it has its own set of problems. These two paradigms are both not ideal, and I would love someone to come up with a better, more elegant solution.
Two other interesting entries are actually related to one another: software repositories and single-file applications. First of all, despite what the article states, applications in Mac OS X are never single-file. What appears to be a single file is in fact a glorified directory, filled with files. Secondly, removing an application in Mac OS X is not as easy as dragging it to the trash; it leaves settings files littered all over the place (cue AppZapper). However, I agree with the original premise: self-contained applications are the way to go. Installers are archaic, and have no place in modern computing. Mac OS X and RISC OS do it the right way.
Which brings me to the software repositories. I would say a combination of self-contained applications and software repositories is a good idea. This would force no one into using complicated applications like Synaptic, as you could still download these self-contained applications manually. I've actually been thinking a lot about these two issues (application delivery and format) and I might write an article about it.
What are the features you would like to see in Windows (or any other operating system for that matter)?