After Gnome2 a big diaspora of Linux Desktop users migrated towards a moltitude of desktop environments: Cinnamon (Linux Mint), Mate (ex-Gnome2 fork), Unity, Gnome 3 Shell, XFCE, Kde,.. this fragmentation is confusing for first-time users and third party software which have to integrate with the DE but the apps which "do the things" on Linux are the same.
How much RAM should waste a Desktop Environment to be cool?
The problem is that a wrong DE could really degrade your user experience on Linux (gray windows, slowdowns), Unity/Mir are targeted towards the future an a convergence Desktop/Tablet/Mobile, Gnome3 is targeted to a non-existant tablet, the truth is that unfortunatly the most mainstream distros abandoned a lot of netbooks with 1Gb RAM or ex-accelerated-PCs-by-broken-proprietary-3D-drivers for the progress (Consume more Ram or need Gpu == better)
Cairo Dock, a modern minimal eye-candy DE for everybody
Cairo-Dock is a Dock. It more lightweight in terms of RAM than Unity and more useful / extensible than Gnome Shell.
The Opengl support is optional and if you want the transparencies you just need Metacity with composite or xcompmgr.
Some tests on a netbook with a 1Gb of RAM.
|unity (without fats)||~ 180 mb|
|cairo-dock + openbox + xcompmgr||~ 172 mb|
|cairo-dock + metacity composite||~ 146 mb|
|gnome3 shell||n/a completly broken|
~ 40mb of difference may be nothing on a modern 8gb Ram pc but are a huge benefit on a 1gb PC.
Installation of Cairo Dock on Ubuntu 13.04
You can install Cairo Dock Session from Ultimate Ubuntu fork N+1, or just with:
apt-get install cairo-dock metacity
Change the window manager from compiz to metacity
Name=Cairo-Dock Metacity Session
Enable the compositing on Metacity, after you log-in type in the terminal:
gsettings set org.gnome.metacity compositing-manager true
More info on: Cairo Dock Wiki.