What should I do with my Sightstone as a Support?

Solution 1:

Always upgrade to Ruby sightstone if you are going to be getting a lot of items that you can use on your carry. Ruby gives you an added cooldown percentage of these items.

I usually find that Frost Queen's Claim is better than the Eye in 90% of cases.

Talisman can be useful in certain cases, if you're facing a very mobile team comp, but the eye is probably better in most cases.

Face of the mountain is pretty good if you are against a lot of assassins and your adc isn't sivir. It's also good if your team has a lot of assassins so you can shield them when they go into battle.

Solution 2:

As a compliment to ChaseC's answer, the main reason to go for one of the combination items rather than Ruby Sightstone is if your support build does not have many on-use items. Tanks are the most obvious example - an off-tank type support may value rushing certain items against specific carries, like taking Randuin's Omen against Ashe. If you are your team's only tank, taking a hybrid item means you can focus your other items on varied defensive items; while Face of the Mountain and Ruby Sightstone grant a decent amount of health, per point armor and magic resist give you more effective health.

Besides tanks, some support players like to build up their AP to make their abilities more powerful rather than rely on item effects. In this case, the argument for hybrid items is basically the same - by getting your gold generation and upgraded sightstone more cheaply and in one item, you can start building toward useful AP items more quickly.