Ubuntu One applet icons for Humanity icon theme.
ubuntuone-client.png need to go into appropriate size folders of
/usr/share/icons/hicolor/24×24/apps
The rest icons go into appropriate size folders of /usr/share/ubuntuone-client/icons/hicolor/24×24/status
Then do
$ sudo gtk-update-icon-cache -f /usr/share/icons/hicolor
to update icon cache.
And finally restart or start ubuntuone.
Download Ubuntu One applet icons for Humanity icon theme from here
Screenshot
