Why can't Microsoft make upgrades this easy. A few caveats: Ubuntu is not officially releasing "Breezy" until tomorrow, so I did this on my laptop (which is not my main Linux development system):
In the Synaptic package manager, under Settings -> Repository, I manually edited my repositories changing all occurrences of "hoary" to "breezy" and I removed the install CDROM as a repository source. I then clicked the "Mark All Upgrades" taskbar icon and then clicked "Apply" - when asked, I chose the "Smart Mode" upgrade that apparently is meant for upgrading to new releases.
One particularly great thing: under "hoary", I had to build and install my own driver for the RT2500 wifi device in my laptop and manually start it. After the upgrade, wireless is on with no manual operations. Note that with the RT2500, when booting Windows XP, I have to manually start wireless.
I am having zero problems with my laptop since upgrading so after waiting a few days I will do the same painless process for installing the new release on my main development computer. Usually, I back up my home directory and do a complete reinstall for new Linux disto releases but Ubuntu has always been so smooth and painless to use I decided to try an upgrade and save all my settings, etc.
Another nice thing is the automatic upgrading of OpenOffice.org to 2.0 pre-release and the latest GNome stuff. Sweet. The upgrade took a lot of wall clock time but only a few minutes of my time (I was working on another computer during the upgrade).
I like the improvements Ubuntu has made since the last release 6 months ago - small steady improvements that would not confuse a non-technical user. If both of my parents were not on OS X, I would set them up with Ubuntu Linux (which incidently also runs very well on Mac hardware).
If I ran Microsoft, I would do what Ubuntu does: bring out a steady stream of small tweaks and improvements and concentrate on stability and reliability. I think that most Windows users would happily pay a small yearly per PC license fee in return for no new gratuitous (market driven to help force upgrades) OS changes and an emphasis on stability and quality.
PS. I am typing this on my Desktop Linux computer - my laptop just started a new screen saver that I have never seen before: 3D ants walking around on a 3D mobius strip -- way too cool :-)