You can run GNOME panel on Ubuntu which is GNOME 3, but made to look like
GNOME 2. Or you can install Cinnamon which adds GNOME 2 but renames
everything so that you do not have conflicts between GNOME 2 and 3.
Personally I hated GNOME 2 and say good riddance, but that is just my
opinion.

Unity deserves time to get used to it. You can really customise it in
12.04. For starters you can remove the global menu and overlay scrollbars
that annoy most users. Then you can add to it or change icons size etc.
Myunity is essential for doing that. You can change themes, too. You cannot
remove the Launcher, but you can change its size and functionality,
including getting it to hide. Dash is more powerful and there are many new
lenses and scopes to add.

It is different, but more powerful than GNOME Shell or GNOME Classic. It
still lacks the power of KDE which is why I have not switched. I also hate
Nautilus and the way they have removed menus and made it useless. Dolphin
is ten times better. I could say the same for many GNOME applications. The
idea of dumbing things down does not work for me. That is why I disliked
GNOME 2. It was dumbed down to the point that it left me screaming for more
and trying a patchwork of applications to get things that just came with
KDE. I think that Unity with its lenses and scopes and GNOME Shell
extensions are helpful, but not a substitute for a powerful desktop to
begin with. To each his own.

To disable auto login go to the settings, user accounts and move the slider
for auto login from ON to OFF.

Alternative method: You can also edit this file: sudo gedit
/etc/lightdm/lightdm.conf and remove your username from the line:
autologin-user=USERNAME. Press Ctrl+Q and save.