Like the code reordering feature (Ctrl-Shft-Alt Up/down) only simpler and quicker. This is available in eclipse (Alt Up/Down) and is extremely useful.
The code reordering feature is a little too smart for quick reordering. I'm never quite sure where my caret has to be to perform the move i want, and what the eventual move would be. A quick move which is not context sensitive is can be much quicker and more useful in many respects.
This is also useful in non code files, like text files, xml files etc.