I may have mentioned that I was thinking of doing a fresh install of Kubuntu Linux when the latest version, 8.04 (codename Hardy Heron), was released last week. That's okay in principle, but it makes for a bigger job as I would have to do some fiddling to get all the applications I use installed and working again. I thought I may as well try out the upgrade.
The upgrade process went very smoothly. It prompted me about whether I wanted to overwrite some setup files. That was a bit confusing as I am not used to the way it displayed the differences. I didn't think I had applied any special settings and so accepted their versions. After an hour or so I was prompted to reboot. As I feared I ended up at a console prompt rather than the graphical log in screen. This has happened previously. I managed to get KDE working via startx by reverting to the free nvidia driver. Eventually I worked out that I could use an older version of the X config file and got the log in screen back. The second issue was a lack of sound. This was not a bug, but there seems to be an extra fader in KMix that does not appear in my session and it was turned down.
So everything that was working before is more or less back. Improvements include being able to set decent screen refresh rates for all users and having them stick next time. I have yet to test sound recording.