You should choose a switching frequency for which the overall losses would be low and the benefits would outweigh the problems. You need to consider the rise and fall times and so the associated switching losses. You also need to keep in mind the gate charge and current required to drive the gate at the frequency you choose. You would also need to think about other components that will be affected by the frequency, such as capacitors, transformer, inductors, diodes, etc.
Did you ask the question just out of curiousity, or is it related to a design?
Hope this helps.
Tahmid.