Like worktop heights, there are a number of factors that you should consider when planning your wall units. Clearly if you are on not especially tall then wall units that start too high will be impracticable.
Your kitchen designer should be able to show you the range of possibilities available so that the design is really tailored to you and the way you use your kitchen.
On the other hand, extending high cupboards right up to the ceiling can be a great way of gaining storage space if you are willing to keep a stepladder, stool, or Olympic rower (!) handy and to allocate that out-of-reach storage to occasional-use items and equipment.