Those who had enough of waiting for Windows 7 can have a preview of the changes in this short video.
Basically, at first glance, it feels the same as Vista. But after digging in, you can see some differences. My best guess for Windows 7 is the multi-touch implementation to PCs and laptops which at this moment was not widely discussed.
Anyway, here is the video. BTW, it is the Windows 7 Beta and that means many things may change.