My question is simple. How can I have the classic Taskbar with Unity at the same time in Ubuntu 11.10?
Somehow in the previous version I managed to achieve that, but now I can not remember how did I do that!
It is no longer possible to use Gnome Panel 2 with 11.10 since Gnome 2 has been deprecated. You can use Gnome Panel 3, though. There are also several other panels to choose from. If you only want the taskbar, then I would recommend having a look at xfce4-panel since it works better with multiple screens and supports more plugins/applets. Lxpanel is also nice, but isn't quite as good at multiple screens. Keep in mind that these panels are just apps, so you install them, run them and remove them just as you would with other apps.
How to install and use xfce4-panel with Unity
How to install and use lxpanel
A second option is lxpanel. This is also a quite nice panel to use, designed for the very light-weight LXDE. It is just as easy to install and use as the xfce4-panel and, like xfce4-panel, it provides other useful plugins/applets.
How to install and use Gnome Panel 3 as a bottom panel
Using Gnome Panel 3 is a little more difficult, since it's less mature than Xfce4-panel and lxpanel, and doesn't have as good GUIs to configure. Furthermore, it defaults to using an upper panel, which will conflict with your Unity panel. So there are a few extra steps to perform.
It is possible to customize Gnome Panel 3 further, but you'll have to do it using dconf-editor, manually entering configuration strings. I prefer the plain one:
I find Unity much better on Ubuntu 12.04.
Both Gnome 3 and Unity are good to manage the whole PC.
Unfortunately, if you use Gnome 3 in Ubuntu or Fedora, there is apparently some bug that causes Nautilus to hang every time it starts, but it starts quicker under Unity.
If you need an interface like "Gnome 2 Panels" or "Windows XP", then you need the "Gnome Session Fallback" or "Xfce" interface.
How to get Xfce steps:
How to get Gnome Session Fallback steps:
Selecting which session to run at Ubuntu logon works like on Windows 8 where you can choose the Metro interface or the Classic Windows XP interface.
Another option to simplify the all Ubuntu GUI (Graphic User Interface) without too many software to install or tweaks to do, I suggest to install "Glx-Dock (aka Cairo-Dock)" and you will get a Mac like interface with better control on what apps are open on the dock itself than the Unity launcher.
Just search for Glx-Dock or Cairo-Dock in the Software Center or Synaptic and install it.