Windows 8 : Metro interface

The Metro interface doesn't look that different, but having your email, photos, appointments and friends pinned to it livens it up considerably - as does the new Metro tile for the desktop, which sports a cute Metro-ified version of the Windows 7 beta fish.
You can also pin libraries here as well as Explorer, but you have to do that from Explorer set to view the desktop rather than from within a library itself.
The improved touch gestures also make it far easier to work with. Swipe from the right edge of the screen and you get the redesigned charm bar; Search, Share, Start, Devices and Settings.
You can do the same thing by leaving your mouse pointer in the top or bottom right corner; first the charms appear as white outlines, then if you don't move your mouse they disappear. Windows assumes you didn't want to trigger them, since you might be moving the mouse to scroll or closing a window at the side of the screen instead. If you are, you don't have to wait for the charms to vanish to do so. Move the mouse towards the charms and the black bar and charm titles draw in on screen.

Start, which is highlighted in the accent colour of the colour theme you choose, swaps between the Start screen and whatever you were doing last. Search is now context sensitive; if you're in IE when you choose it, you get results from Bing first.
Swipe up from the bottom on the Start screen to get a quick link to the All Apps view, which is now neatly organised into program groups, arranged alphabetically.
As you swipe across the Start menu, it stops with the group of tiles you've swiped to line up under the word Start; this bouncing into place is the promised 'speed bump' to help you navigate around. Scrolling with a mouse works far better - if you push the mouse past the edge of the screen, the tiles scroll as if you were swiping with your finger.

This works so well you'll miss it in apps that don't support it, such as Photos, where you have to go back to grabbing the scrollbar or use a touch pad or Microsoft Touch Mouse, which enables you to swipe sideways.
The Semantic zoom feature now works too; pinch to shrink the tiles on the Start screen to tiny thumbnails so you can see everything at once or move an entire group. Select a group and drag it down to get the option of naming it.

This is also the view you get when you drag a tile you're moving to the bottom of the screen, which makes it easier to move an item a long way across the screen without disturbing the arrangement of all your tiles and groups.
As you drag a tile between two groups, when you position it between them a vertical grey bar appears to show that you're creating a new group to put it in.
Switching between apps is now far easier. You can still drag in the next app in the stack from the left edge of the screen to be full screen or to snap into a side window, but when the icon of that next app appears, you can also drag it back to the edge to get a vertical pane of thumbnails.

This only shows six thumbnails of recent apps (including the desktop if that's open) plus the thumbnail for the Start menu. Tap a thumbnail to open the app or drag it to choose where on screen it appears.

You can get the switching pane using a mouse by leaving the mouse pointer in the top or bottom left corner of the screen until a thumbnail appears (the next app at the top, the Start menu preview at the bottom). Drag down with the mouse and the thumbnails appear. If you want to see all current desktop apps and recent Metro apps, use Alt+Tab instead. Win+Tab makes the switching pane appear.

You can close Metro apps without restoring to the task manager. Drag down from the top of the screen until the app you're looking at shrinks down to a thumbnail and keep dragging that off the screen to close it (it's a longer swipe than when you use a quick finger swipe down from the top or up from the bottom of the screen to get the menu bar inside an app).
That works with a mouse as well. Or you can use Alt+F4, just like with a desktop app.

You can type quite well on screen. The large touch keyboard is a little better laid out now, and has predictive text and spelling corrections.
The thumb keyboard layout still has the alphabet split between the two sides of the screen where it's all in reach of your thumbs, but there's now a numeric keyboard in the middle to make it faster to type passwords (or indeed, numbers) and you can resize the keyboard.

The new notifications in Metro work well; they pop up in the top right corner of the screen where they're not likely to be in the way and you can tap for options. So the first time you put a USB stick in, you can choose whether to open Explorer or do something else, and that will happen automatically next time you insert it.