For all of you who like to use the terminal command lines, and prefer the keyboard over the mouse, has been made gnome-open
To use it your gnome should have the appropriate file associations so it can open the files with the proper application
Where file is the file you want to open, it could be any file you have right to access, for example
gnome-open pic1.jpg gnome-open file1.doc gnome-open music.ogg
be sure to change the name of those files for files you have on your disk, those commands will make gnome to open the appropriate application and the file you are trying to use.
I find this command very useful as I came from the old days, with MS-DOS or PC-OS and from the old Linux with where we just almost never used X, so I prefer to use keyboard rather than mouse.