well, 52 smithing is really only gained through getting the anchor, which i find is a beastly weapon.
so, honestly get the 52 prayer. but only because its given to you while you do the quests to get anchor. anchor is an amazing wep and, to have it on your pure will be one step closer to being perfect. [through my eyes, a perfect pure is a pure that has everything it can possibly have in its possession]
good luck!