To install a version of gnome-do with the docky theme I first had to add the following repositories.
deb http://ppa.launchpad.net/do-core/ppa/ubuntu intrepid main
deb-src http://ppa.launchpad.net/do-core/ppa/ubuntu intrepid main
Then install gnome-do:
sudo apt-get install gnome-do
Once installed open up Gnome-Do and switch the Theme to Docky. This is smiler the OS X dock and also has Quicksilver style searching.
This tool has a nice layout and a very powerful text based action system but there is currently only the primary theme and very few options to control the UI. It does Stack multiple instances of an application together but they window manager control of that stack is less then optimal. Also the dock itself is part of the theme not the main program so there are no way to extend the dock with plug-ins. It is a a simple list of shortcuts and running applications.
Avant Window Navigator
To install awn just run:
sudo apt-get install avant-window-navigator
This is a much more feature rick dock utility with a multitude of options and plugins, minus all the Quicksilver features.
This dock did take a bit more to get configured though, I have two monitors and where Gnome-Do automatically came up on my primary display awn favored the left most monitor witch happens to be my secondary monitor. There was no apparent way to drag it to teh correct locations nor option to change it. After a bit of fiddling I wound two settings that worked for me. To fix this problem I used gconf-editor to change the following properties.
/apps/avant-window-navigator/monitor_height = 1050
/apps/avant-window-navigator/monitor_width = 3360
/apps/avant-window-navigator/force_monitor = true
/apps/avant-window-navigator/bar/bar_pos = .74
The first two settings configure the virtual screen size taken from gnome-display-properties and the third option causes awn to use the virtual screen size instead of the size of the first monitor. The final option adjusts the position the dock, now centered between the two screens, to the center of the right screen.
Note: The property editor was rounding .75 to .7 so I actually had to run the following command to set the property.
gconftool-2 --set /apps/avant-window-navigator/bar/bar_pos .74 --type float
As it turned out awn has its own share of hiccups including:
There is no way to get multiple instance of the same application to stack up nicely.
Multiple windows sharing the same name will cause the process icons to fall away and reappear at the end of the list. This is visually confusing but would not be an issue if process could stack.
That said there are many nice plugins for the dock including a embedded terminal and a multitude of themes and visual tweaks, though I wish there was an option to make auto-hide only hide a set distance instead of completely hiding the bar.