For those who prefer classic Gnome-style application menu, there’re two replacements in Ubuntu 11.10 Oneiric: classicmenu-indicator for Unity, and app-menu-extension for Gnome Shell.

1.) In Ubuntu Unity using classicmenu-indicator

This is an applet indicator in the system tray area. Ubuntu 11.10 and 11.04 user with Unity can install this by adding following untrusted ppa. Check the package from ppa:diesch/testing before.

sudo add-apt-repository ppa:diesch/testing
sudo apt-get update
sudo apt-get install classicmenu-indicator

2.) For Gnome Shell there’s a classic style app menu extension

Run following commands in a terminal window, only provides package for Ubuntu 11.10 so far.

sudo add-apt-repository ppa:webupd8team/gnome3
sudo apt-get update
sudo apt-get install gnome-shell-extensions-apps-menu

After this, restart gnome-shell by Alt+F2 and run “r” (without quotes) or log out and back in.
Then in gnome-tweak-tool (sudo apt-get install gnome-tweak-tool, then search Advanced Settings) Shell Extentsions, enable this extension:

This ppa also contains many other gnome-shell extensions, check ppa:webupd8team/gnome3