The standard will be the army blue beret. Corps/regiments may choose to wear a different colour beret, for example the RCR polled its guys and they had to decide between blue or khaki.
The full colour forage cap will be for each individual regiment and corps to decide if they will wear it. At this time, all 3 regular force infantry regiments have decided to wear berets and forego the forage cap.
The khaki service cap will be an optional item (costing money to the member I assume) not to be worn on parade. This would be an item for anyone who wears No 3 as their dress of the day, SADs, or any other event where you are in No 3 but not on parade. Frankly I don't see it being used much outside the NCR or unit command teams who maybe wear service dress for conferences in Ottawa. Will I buy one anyways, as a class B reservist using the army to fund his masters and PhD? Probably.