How do I change the order in a list of options?

[Steven Vollom]

If I want to choose a different media player from the one that is default, how 
do I change the order of those that are available to choose from.  For 
instance Media Player in my default, right now.  But I really want Kaffeine to 
open when a media player is not specified.  I understand that the first in line 
is default, so I would like to move Kaffeine to the top.

I also would like Empty Trash as the first choice when I right click to empty 
trash.  And Move to trash up there too.  I use them all the time, and in 
various packages the option puts them in a different position.  Thanks!

Steven