Depending on the service, tipping in Vegas is customary.  If you want a room with a view a good suggestion is to tip the front desk clerk and ask if they have an upgrade or a room with a better view.  Explain briefly that you are getting married and want this trip to be very special.  Same goes with the concierge, if they are coordinating one of your events or outings be sure to tip them.  Anywhere from $20 on up is acceptable.