Depends on what type of vacation and for how long.
A couple years ago we went to Hampton Beach (New Hampshire) for 5 days and spent about $1200 for everything - food, hotel, etc. This was for 3 adults and 1 child (DD was 18 months at the time).
Now this coming vacation is Disney and it is a considerable amount more. We have hotel, dining plan, tickets, air all paid for and will have about $1800 in additional spending money for 8 nights.