Early reaction to Windows 7 is that it's a winner. Could the successor to Vista be Microsoft's last gasp, or does open source have a formidable new rival to Linux?
Most every current desktop-oriented Linux distribution has at least some form of support for multiple virtual desktops. The default seems to be two desktops, which seems to be about the limit of what people can handle -- more than that and you run the risk of forgetting what's open where. But if you like being able to put windows entirely out of sight and don't also tend to put them out of mind in the process, multiple desktops will probably work fine for you.
The current Linux desktops also have some sort of meta-organization feature akin to Windows's Flip view or the Mac's Expos. The most common example is GNOME's Beryl, which also includes window effects like glass, fade in / out and zooming in / out to see thumbnail versions of all windows. The best part is that these effects work well even on not-so-recent hardware.
My own Sony VAIO notebook, with a non-Aero Glass compatible Intel 915GM video chipset, runs many of the Beryl 3D effects without hesitation. None of the advanced video effects in Vista or Windows 7 is available on the 915 chipset-- and at this rate, never will be.
The Single Best Thing
With each successive revision of both Windows and the various Linux distributions, there's less to tinker with. A blessing, to be sure, but the details of what's been improved in both Windows 7 and the most recent distros is worth talking about.
Windows 7's contextual search returns a broad range of task-based functions as well.
The single biggest leap forward Windows 7 has taken in this regard is sharing of files, via the new homegroups function. Put the files you want to share in a given folder or add them to a library of folders, provide everyone with a specially generated password to access them, and you're done. On my own mini-network of three Windows 7 computers, it just worked.
This is one of the few things that when Microsoft gets right, they get it exactly right: they understand how to bring computing to people who otherwise don't ever think about it. Linux, for all of its flexibility, doesn't yet have the same level of dedication to making this sort of thing happen -- if only because up until extremely recently it wasn't a requirement. To be fair, sharing files and folders in Ubuntu actually isn't that complicated -- see the official tutorial for yourself--but Microsoft deserves credit for automating as much of the process as possible in a way that most people will find useful.
Another deeply useful thing Windows 7 has introduced -- a refinement of a feature in Vista -- is the way searching and contextual help have been made it easier to figure out how to do things. Type "networking" in the Start button's search panel, and you'll see a bevy of options specifically related to networking features. Do the same thing in KDE (which also has a search function in its main menu), and all you get is a generic "Search the web" link. (Just "network" will take you to the network control panel, but the range of results in 7 is far more detailed and task-specific.)