Before the Ubuntu upgrade Link to heading
Before upgrading, check if all your non-Ubuntu repository applications are available. For XBMC you can check the XBMC roadmap
After the Ubuntu upgrade Link to heading
We need to reinstall all applications, which are not in the Ubuntu repository. They were cleaned up automatically.
Installing XBMC Link to heading
See here for all instructions: Installing XBMC on Ubuntu
Installing DropBox Link to heading
Download the debian package here: dropbox.com/downloading Linux
Just open the downloaded Debian package (Ubuntu x86 .deb).