As you anticipate, GNOME 2 is almost dead. Compiz is not. It is the window
manager used by Unity and has Canonical's backing. The problem with GNOME 2
is two-fold. GNOME no longer supports it and GTK2 is not capable as a
developer platform which is what forced GNOME to produce GTK3 and GNOME 3.
The second problem s why it is more likely to die an ignoble death. Other
developers can support GNOME 2, but they cannot fix the shortcomings of GTK
2. That is why Mate, IMO, is not a good choice. The GNOME 2 applications
will lack features and some will no longer be available as time progresses.
The combination of GNOME 2 and Compiz may have once been good, but it has
no future. That produces a problem for fans of GNOME 2. Where do they go?
Mate is one option, but it is not a drop in replacement unless you were a
Mint user previously. The panel is at the bottom and it uses Mint menus
instead of GNOME2's top panel and familiar menus. So there really is little
reason for a GNOME2 user to move to Mate. I could say the same for
Cinnamon. It is for Mint users. It is a modified GNOME Shell built on top
of GNOME 3 with Mint menu and bottom panel. Fans of GNOME 2 will find it
unfamiliar.
The best choice IMO is XFCE, but you need to make some modifications to
make it look like GNOME2. You can move the panel from the bottom to the
top. You can install Compiz and use it as the window manager.
www.ghacks.net/2010/07/11/run-compiz-with-xfce4/
You can use any Compiz based distros or install it in your current
distribution without having to re-install. I would recommend Mint XFCE,
Arch with XFCE, Xubuntu, or Debian 6 with XFCE. Arch and Debian are more
for experts. Mint 13 XFCE and Xubuntu 12.10 (newest) are newbie friendly.
Arch and XFCE with Compiz
http://www.youtube.com/watch?v=W3IWUOH9LI0
The ghacks link above will work for either Mint 13 or Xubuntu.
How to change the XFCE panel:
http://docs.xfce.org/xfce/xfce4-panel/preferences (unlock it first then
click a panel handle and drag it to the top)
If you want to stay with GNOME2 and Compiz combination the longest then
install Debian 6. You can transition to XFCE and Compiz later.