Today, finally install Ubuntu 9.10. I've only to update the system for several hours, but everything seems to work smoothly.
II used my usual technique to install the new version of Ubuntu. I'm using a separate home and root partition. To use a custom installer Ubuntu partition and converted small partition using the new ext4 file system and use the old boot partition as the new boot partition. Setup has finished in less than nine minutes. Before leaving the live CD, opened a file browser (Alt-F2 and «gksu nautilus») to remove the old configuration files (files and folders from the period in your home directory). With the exception of a few applications I don't want to have to reconfigure, I moved the old config files in the backup location. This allows me to start new applications and application configuration, without having to backup and restore my data.
Ubuntu 9.10 is out for a while now, so surely everyone knows what's new. I'll just mention a few things I've found setting up the new system.

The default theme (and especially the icons) are much improved in Ubuntu 9.10. But I'm not a fan of orange so I installed the elementary theme (just the GTK and icon themes). I'm getting a warning that I don't have the right theme engine installed, but I like how it looks so I just ignored it.
The first thing I noticed after installing the Nvidia drivers and getting Compiz running was how moving windows around looked jerky. I reapplied my settings from Make Compiz Run Smoothly and Without Tearing to fix Compiz's refresh frequency and now it's back to being smooth.
I'm using Chrome for web browsing now. Before the upgrade I was using the daily builds of Chromium. I used Google's bookmark sync to save my bookmarks, but couldn't restore them because the official release of Chrome lacks the sync feature. I couldn't find a way to get at the bookmarks online (why isn't this integrated with Google Bookmarks?)(update: A commenter points out that bookmarks are available in Google Docs), so I copied .config/chromium/Default/Bookmarks from my backed up configuration folder to the new Chrome configuration at ~/.config/google-chrome/Default/Bookmarks.
I installed Ubuntu Restricted Extras as usual to install Flash, Java, web fonts, and media codecs. For some reason this didn't install the Java plugin. I installed 'sun-java6-plugin' separately to fix this.
After installing the latest version of GNOME Do I was pleased to find that it can now open my home folder. This bug (I think it was actually in Nautilus) has been annoying me for ages.
I added the new Wine PPA to get the latest versions of Wine. Trying to install the 'wine' package failed with a «unresolvable dependencies» error. Installing wine1.2 instead worked (all 'wine' should do is install wine1.2 anyways). There's a forum thread about this issue.
Ubuntu 9.10 has a little mail icon near the notification area called Indicator Applet. I'm using web-based mail and instant messaging, so the Evolution and Empathy integration aren't useful for me. I am using a utility called Gmail Notifier which integrates with Indicator Applet and Ubuntu's notification system. When I get a new email it pops up one of Ubuntu's fancy notifications and lights up the mail icon.

[via tombuntu]