Here is the rule of thumb:
If you have eight-foot ceilings we recommend your cabinets go all the way to the ceiling. Since 8 foot ceilings are not too high not having your cabinets to the ceiling may make your cabinets look short. Having your cabinets touch the ceiling will give you extra storage and will eliminate having to clean the top of the cabinet.
If you have ceilings higher than eight feet it is a good idea to leave some space in between your ceiling and the top of your cabinets, otherwise your cabinets may be too high. Most people do not put stuff that they use on a regular basis higher than they can reach. However, it would not be wrong to go all the way up to the ceiling. This will give you added storage for the kitchen appliances that you may not need to use all of the time.
The most important thing to remember is that you should always do what you feel comfortable with!
