Windows 7 is Microsofts best OS so far. It has a great look, much faster than Vista, more and better features.
The installation went really smooth, the OS was fully working after around 30 minutes of installation. After I started it the first time, I did an windows update search fro drivers, and it installed every single driver automatically, so I saved a lot of time with installing every driver separately.
User-friendlyness and speed
Some users say Windows 7 is just a service pack for vista, but in my opinion, it isn't. Windows 7 is more user-friendly than Vista, and it's much faster too. Doing things like switch between wireless access-points is a lot faster and easier now, just right-click and choose the connection, instead of opening that wireless connections window in Vista. Really good in school on the breaks if you want to LAN with your friends, but have to do it on a separate router than the schools ;).
Also ReadyBoost has been improved a lot. In Vista, I didn't feel much difference after I plugged an USB flash drive in and used it as extra memory, but in Windows 7 I feel a slight improvement in speed.
The new taskbar
The new taskbar in Windows 7 is awesome. Instead of the cluttered taskbar in Vista, now there are only icons without labels, so now you can have more programs open at the same time without getting really small buttons on the taskbar. Also, now you can pin stuff to the taskbar, so you can just click on the program you want to use, without going into the start menu or from the desktop.
Also, there is a right-click menu. Not many software do use this function (obviously as Windows 7 hasn't really been released yet), but the software that follows does (MSN and IE8 is the only ones I've seen sofar). Also, it shows "recent opened documents" in this list, which is great for text editors like word or other editors, like Dreamweaver etc. Want to continue edit one of your documents you didn't finish? Just right-click and choose it from the list :D.
There is a lot more features I haven't tried yet, so I leave them as a suprise for you ;)