While you've no doubt seen a few of these features mentioned before, most of the items below have received the least attention from Windows 7 previews. It's these less sexy, but very useful features, that make me think the more I use Windows 7, the less chance I'll ever use Vista or XP again.
Libraries Make File Management Easy
Windows 7's Libraries are a huge leap ahead of file management in previous versions of Windows—rather than dealing solely in files and directories, they are a virtual location that can aggregate the content from multiple places at once.
Like most Lifehacker readers, I'm using Dropbox to sync my files across multiple computers—including a subset of my music collection. Rather than trying to use hacks to sync directories outside my DropBox folder or dropping to the command-line to create some symlinks, it was as simple as adding my Dropbox music collection folder to the Music library.
Once you've added your folders to a library, they will show up anywhere you navigate to that library, including the common file Open/Save dialogs—makes dealing with complicated folders a thing of the past.
Jump Lists Add Quick Access to Common Features
Windows 7 replaces the taskbar context menu with a useful list of frequently used documents, tasks, and even allows you to pin documents or shortcuts to the menu. You can access this by right-clicking on the taskbar button, or you can hold down the left mouse button and "drag" the mouse pointer up—an easy motion for touchscreen displays.
Want to quickly access Internet Explorer's Private browsing mode? Simply right-click on the icon and you can launch a new private window—you can create a shortcut for private browsing in earlier versions of Windows, but it's not quite the same.
Want to access a few websites quickly? Just drag the icon from the address bar down to the taskbar icon to pin it to the top of the Jump List—now you can get to those websites in a flash, whether Firefox is open at the moment or not.
Put the Taskbar Back to Vista/XP Style
If you simply can't get used to the new Windows 7 taskbar, Microsoft was (thankfully) smart enough to let you change everything back to what you were used to in previous versions of Windows.
Just head over to Taskbar and Start Menu properties, choose to use small icons, never combine, and then un-pin the applications from the taskbar—though you may want to try using the "Combine only when taskbar is full" option to get the best of both worlds.
If you're the screenshot tour type of person, I've written a full walk-through tutorial to changing the taskbar to work more like Windows XP or Vista, and to complete the picture you can also add the quick launch bar back to the taskbar in Windows 7.
Run Apps as Another User
If your favourite application doesn't support multiple profiles, you can often mimic this functionality by running the application as another user. In previous versions of Windows this wasn't quite as simple—now you can just right-click on any application while holding down the Shift key and choose to run it as another user.
Hidden Items on the Send To Menu
Most Lifehacker readers probably know how to customise the Send To menu—just type in shell:sendto into the address bar, and add or delete shortcuts from the list. But Windows 7 makes it easier with a bunch of secret items on the Send To menu.
if you hold down the Shift key while right-clicking on a file or folder, you'll see a whole list of extra items that are normally hidden. The extra menu items are simply the list of directories under your user folder, but it's a useful feature that makes you want to start using the shift key every time you right-click just to see what comes up!
Automatic Desktop Wallpaper Shuffling
Let me start by saying that I've never been a big fan of rotating wallpaper—in fact, I use the same background image so often that there are constant requests for the awesome Mario World wallpaper from my screenshots (hint: we've already covered it in our list of killer retro gaming wallpapers).
Windows 7's simple, easy, and awesome wallpaper shuffling has won me over. I'm officially a convert. Not only does Windows 7 include a ton of absolutely killer wallpaper images, but you can select more than one at a time with the checkboxes (or holding the Ctrl key) and then choose to rotate them every so many minutes.
The fun doesn't stop there, however—you can right-click on the desktop any time you want to skip to the next desktop background image. Since the default Windows 7 theme uses a ton of transparency, your whole desktop theme will appear to change to fit the new colour scheme—it's beautiful.
User Account Control is Streamlined, Less Annoying
Without question, the biggest complaint on Windows Vista is the completely annoying UAC prompts that were even ridiculed in Apple commercials—so irritating, in fact, that getting rid of it remains an in-demand topic.
That's changed significantly in Windows 7, however—common (geeky) operations like copying system files only require a single prompt, and the whole system has been streamlined a great deal to be less annoying. If you're still getting too many prompts, you can simply type "uac" into the start menu search box, and then drag the slider down (though you should be warned you are decreasing security).
What about you? Has Windows 7's uber-slick interface won you over? What features really stand out for you? Tell us in the comments.