Make Nautilus navigate to the first file beginning with the typed letter
When I press the letter N in a folder in Nautilus that contains files whose names start with a letter N it jumps to the first one of these files. Pressing it a 2nd time will begin the search by name (a little box pops up in the lower right hand corner).
There isn't a way to change this behavior using Nautilus. I believe you can use other file explorers though such as mc
(aka. midnight commander - terminal based) or Dolphin (KDE).
There's a pretty extensive list of file explorers on wikipedia. Check out the section of *nix ones for other alternatives.