You pick your grade of water based on your application:
IC requires the use of 18.2 MegaOhm water-this grade of water is distilled, deionized, degassed, run and rerun thru a reverse osmosis process.
For HPLC applications-mot are done using UV detection so HPLC grade water would be appropriate since it is assayed for organics which absorb in the UV range. It would not be appropriate and is not appropriate for IC applications since it is not assayed for mineral content.
It all depends on your application.
For an application that involves creation of colloidal gold deionized water, at minimum, is a requirement.