Docky

Although, MacOS has long moved forward from the 3D tray like look Docky hasn’t. Not by default, at least. Not many Linux docks can boast of being as polished of an experience as Docky. All the polish and nice animations do mean that Docky is not quite as lightweight as Plank. It is still not as resource hungry as something like Cairo Dock though. Recently, the dock has even gained integration with the GNOME desktop making it even better as an Ubuntu dock. Even if you don’t use GNOME, you can still switch between 2D and 3D style dock, change themes, enable or disable intelligent hiding, add or remove docklets, and turn on or off a panel mode. The docklets or Docky widgets help provide information such as a clock, weather, and CPU usage.

Docky is available officially in the Ubuntu repositories so there’s no need to add any PPAs.

$ sudo apt-get install docky

Cairo Dock

$ sudo add-apt-repository ppa:cairo-dock-team/ppa
$ sudo apt-get update
$ sudo apt-get install cairo-dock cairo-dock-plug-ins