i gotta disagree on that.
Win 7 is a significant rewrite of Windows, its GUI is an update to Vista but thats about it. Of course it shares the same core kernel but its has to otherwise it wont be Windows.
Every new OS is essentially a big service pack to the old one.
As for the linux side of things. As long as you have the apps you need its great. I use it as my file server and torrent box (to get linux iso's of course) i reckon linux is great for a specific tasks but not what i could you it as a desktop replacement to XP or OSX its just not supported by enough software vendors (this will change soon though) you have the Option of Wine to use Windows based apps in linux which is great though.