Fast? That's the understatement!
I've thrown Windows 7 on Pentium III systems with 512 meg of ram and found it out does Windows XP SP2. Windows 7 runs on a smaller footprint of hard drive. If you use a DVD install vs the USB you can save 2gb of required space and get it to install on an 8GB solid state drive. It gives the Aero interface capability on an Acer Aspire One ($300 NETBOOK). It installs off USB in 8 minutes on a 7 year old laptop.
Faster? Boy you guys are holding back. Windows 7 is the greatest most incredible technological leap Microsoft has put forth into the market. The compatabilty is better. There are some things I liked being packed into Vista that aren't in Windows 7 but a lot of that has been offloaded into "The Cloud" with Live.com. So you don't actually lose anything.
Ok now I *DO* have one comment to the team regarding Movie Maker. You had an astoundingly powerful and flexible version in Windows Vista. And there are hacks to copy Movie Maker from Vista to Windows 7 (and they work beautifully) but PLEASE make "Live Movie Maker" be as full featured as it's Vista Cousin. Movie Maker 2.6 (the downloadable version) is a far cry from Windows Vista Movie Maker 6.
Yes people use Movie Maker. It *IS* an excellent video editor and a great way for a lot of people to get started.
So having said that, keep up with the performance boosts. I can't wait for RTM! It's about to get rockin' busy at work between Windows 7 and Server 2008R2! Wooooooooooooooooooohooooooooooooooooooooooooooooo!!!!!!!!
Sean