Tipping Guidelines

 Bell Services/Porter   $1-2 per bag (arrival and departure)
 Maid Service/Housekeeping   $1 per person, per day
 Dining:
    Full-service
    Buffet-service
    Room Delivery

  15-20% of total bill
  15% of total bill
  10% of total bill
 Lounge/Cocktail Waitress or Waiter   10% of total bill
 Taxi   15% of the total fare or 25¢ a minute, whichever is higher
 Towncar Service   10-15% (arrival and departure)
 Valet Parking   $2-5 (arrival and departure)

A good rule of thumb, if you have had exceptional service, tip a bit more than normal.