I've actually started using spellthief on her, and getting mana regen (in the form of catalyst) asap. I later build that into a righteous glory, which provides a BETTER speed boost than the coin active (when chasing at least) and then does an aoe slow similar to randuins, while still having the hp/mana regen at level up.
I've also seen some people get warmogs or visage on her, for the extra regen, and while neither is a particularly fantastic item, I would say both have their uses and places.
Definitely get the sightstone of course, and locket/frozen heart as needed. And then whatever else you like. I just personally, as raka has limited hard cc, prefer to have frost queen AND righteous glory for the added cc, even if it is just slows.
-T