On the Collector's edition, I still have the habit of trying to use the C-stick to rotate the camera--because I played The Wind Waker before Ocarina of Time, so... xD So, I always make sure in that version, to never have bombs--or anything that has a limited amount--equipped so I don't waste them.
But usually:
Child: boomerang, Ocarina of Time, and the third one usually depends--usually a mask or something, because I usually play around. =)
Adult: hookshot/longshot, Ocarina of Time, and this one also depends... sometimes it's the iron or hover boots, and sometimes it's the bow and arrow.
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In OoT3D, I can unequip stuff pretty easily and have nothing at all equipped. Except for now, I have one too many items to have them all stored, so I usually have just the boomerang out as a child, and just the longshot equipped as an adult. (all of my stored items are in alphabetical order /ocd)