gedit would be very cool if it were able to allow folding of text, etc.  Implementing vim's folding methods would be cool, as it would allow people to set up folding that works equally well in gedit as it does in [name your favorite folding editor].

What I'm picturing is just having the facility to automatically create/recognize folds via one or more gedit plugins.  What would be needed is for the plugin to parse the code, and decide for a given line what fold-level the line belongs to.  Then, gedit would simply add the folds as the little [+] / [-] boxes which can be clicked with a mouse to fold/unfold sections.  (of course keybindings for folding/unfolding sections would also be important to have the ability to configure...).