This is a CD player only. It lacks a power amplifier. You'll need active speakers therefore or an additional amplifier.
There is no such thing as optimum speakers. Every kind of speaker makes a compromise between cost, size, weight etc. Selecting a good pair of speakers is also a matter of personal taste. If you want speakers that give you pleasure when listening to them you'll have to test-hear them. Ideally in your home where they will be used, not in a showroom that usually does not have the typical sound environment as e,g, your living room.