Presidential vacations cost taxpayers millions of dollars due to the use of Air Force One, and the cost of moving the entourage that accompanies the president (to include the advance team that goes to the vacation location before the President arrives) and their lodging.
An example can be found here of a $4M vacation, most of which is covered by taxpayers: http://now.msn.com/obama-vacation-costs-prompt-complaints
The average US citizens cost of Hawaii vacation for two: http://traveltips.usatoday.com/average-cost-hawaii-vacation-two-34699.html
The President is not being a good steward of the citizen's taxes when he takes a vacation that is well beyond the amount spent by the average citizen.
The President should lead by example when it comes to fiscal responsibility.