Some of my colleagues have Apple Macs and use an application called ‘Quick Silver’ for managing frequently use application/scripts/text files/notes/ims/etc.
I was impressed with what one could do with it and began looking for something similar on Ubuntu.
There is a clone for Gnome called Gnome-Do [ http://www.gnomedo.com ] that lives up to the task pretty well from what I can gather so-far. There are some good updates in the ‘Intrepid Ibex’ release (8.10) that are not in the ‘Hardy Heron’ release (8.04), such as a more complete and useful preferences menu, more plugins and managing them individually through the applications preferences.
Try it out, after installing gnome-do, you need to set it up to launch at gnome login (easily done via the preferences in the intrepid version). Then you can invoke it with the SUPER+SPACEBAR short-cut.