OK, Joel, you asked for it. RANT TIME!
So this means we'll need to have every version of .net installed if we expect to be running .net apps? That's like downloading a cool game from say 3 years ago, and you have to go download DX 7 for it to run. Then you decide to play an older retro game, and have to download DX 1 or 2 for it to run. That's what I see in the future if M$ doesn't quickly get their act together and make the new versions of the .net framework completely backwards compatible. My opinion is .net is fine for asp.net web apps, but other than that, and especially for a Windows forms app, let's just forget about it.
And you wonder why I still think a native win32 app is the best.
Why do you think Borland after Delphi 8 (which was only for .net) has made the next 2 versions able to compile .net or win32 apps? Out of all the developers that were at a Borland conference, only like 3 or 4 out of about 100 people even planned to use .net for their project, and that was for a web-based asp.net project. Not one of them planned to use it for a Windows Forms application.
For your reading pleasure if you're totally bored:
Win32 vs. .Net
Feel free to flame me, now.