The big thing with Longhorn is going to be the new file system, WinFS. It'll make Longhorn revolve around the .Net framework, mainly. Of course, this is going to make people even more dependent on microsoft, because .Net is extremely proprietary, and it's main purpose for being the central point of the next Windows is so that they can attempt to force it as a standard upon the rest of the world, and create another monopoly. By using this filesystem to make Longhorn compatible with only .Net, they're going to lock out all competing technologies.
When it boils down to it, Microsoft isn't releasing windows updates for windows, they're doing it for their other technologies so that they can force them to become standards, and make a ton of cash off of them. Microsoft has been releasing crap OS's since 95, and everyone has been brainwashed into buying it, thinking it's actually good.
So basically, I think Longhorn is a way for Microsoft to shove .Net down our throats, and we need to do something about it. Maybe a competing company can take it to court before Longhorn is released, forcing Microsoft to make their software open for other technologies...