Well um, since there’s so much going on around Win7 and everyone’s already blogging about it, what I’m going to do is just provide you with a collage of some of the most important stuff collected through various other sites. If you actually want deeper coverage I suggest you visit one of the original sites Win7 stuff is being posted to.
User Interface
Multi-touch
http://www.news.com.au/technology/story/0,25642,24569778-5014239,00.html?from=public_rss
The new Snap feature lets you expand and maximize windows simply by dragging them to different edges of the desktop. Drag a window’s top edge to the top of the screen to maximize it, and drag it away to restore it to its original size. Line up any window’s edge to either side of the desktop and that window will snap to fill up that half of the screen. Do the same with another window on the other side and you’ve got two equal-sized windows on either side of the screen.
http://www.webmonkey.com/blog/PDC_2008%3A_The_7_Coolest_New_Features_in_Windows_7
First impressions: the revamped Windows 7 taskbar
http://www.theregister.co.uk/2008/10/28/windows_seven_review/
Systray Improvements
http://www.zdnet.com.au/insight/software/soa/Windows-7-Official-screenshots/0,139023769,339292888,00.htm?feed=pt_windows_7
Icons represent devices
Jumpstarts
Multiple Windows of Same type
Performance
The operating system itself has gotten a considerable amount of reworking below the presentation layer. If M3 is any indication, that work has led to a tighter OS, and by "tighter" I mean that resource requirements are being lowered
http://www.cio.com/article/457622/Windows_Takes_On_Apple_and_IT_Needs?source=home_ln
"today at his keynote at PDC 2008, [Steve] waved an Asus EeePC running Win 7 with a 1GHz processor and just 1GB of RAM"
http://www.gizmodo.com.au/index-4.html
For starters, even the early build of Windows 7 feels like a fast, stable environment. There's a lot going on behind the scenes to make the OS more usable, one monumental improvement being how video memory is allocated for unseen windows. (Hint: It's not.) The result is a highly responsive machine that gets decent battery life.
Boot-Up Time - 25 seconds
Changes include a reduction in the overhead of the desktop Windows manager so you don't need to turn it off when developing, a "substantial" reduction in the disk I/O when reading from the registry, and an attempt to reduce the memory footprint of the core Windows 7 install.
http://www.theregister.co.uk/2008/10/28/windows_7_vista_lessons/
Windows 7 DWM cuts memory consumption by 50%
Security
Set prompts using UAC's slider - Sliders are used regularly as a way of adding/removing config details
Bitlocker Drive Encryption tool
Driver Protection
Driver Protection helps prevent the operating system from starting drivers that are known to cause stability problems.
http://www.activewin.com/screenshots/windows7/Windows%20Live%20Family%20Safety%20Filter.png
Video