1. Justin Upton
While Davis, Gordon, Cespedes, and Desmond all have their strengths and weaknesses, the best overall position player left on the market is former San Diego Padre left fielder Justin Upton.
Upton provides power akin to Davis, better speed than all the options on this list, and decent enough defense to make him the most valuable player left. Add to that his relative youth compared to the other players on this list, and Upton holds some substantial value this offseason.
It remains to be seen what kind of contract Upton can get, and from whom, but it appears likely that he will make $20+ million a year over six or seven years, or basically what Chris Davis was already offered.
Regardless of what he is able to get, Upton may be the best short term and long term option of any of the position players still left on the market.