Quick Silver
I am not sure how i stumblled upon Quick Silver, but it should be the first App to be installed on every new mac.
Quick Silver is a utility that extend the Finder capabilities, it is a combination of a search engine (like SpotLight and GoogleDesktop) with right click abilities, and then some (Open, Delete, Rename, Mail to...).
the idea is simple (like all great things are), to allow a user from the keyboard to perform (almost) all actions on a resource (Application, File, Folder, Network share, URL, etc...)
there are many advanced abilities, several User Interface, and endless list of plugins,
Quick Silver is available for mac only, (windows users have replica like Launchy, and SkyLine) QS is available for download from these locations:
BlackTree - Home Site
SoftPedia - Mirror 1
MacUpdate - Mirror 2 (love macupdate)
VersionTracker - Mirror 3 (track versions. what a great idea)
hope you will love QS as much as i do.