A close second would be the small sized rectangular granny: http://www.ravelry.com/projects/jruss95/granny-blanket-6
These patterns have
- few ends to stitch in,
- don't have to be pieced,
- can be made with or without a border,
- don't require complicated counting,
- are endlessly variable, even while in progress,
- don't require blocking, and
- look nice when finished.
What else could I want?