Since X was my first Final Fantasy im gonna go with Aeons. It just has a nice ring to it. Makes them sound kinda mystical. I never liked Summons it just sounds kinda lazy but I do think it has its place in the older games becuase it suits their simplicity. I dont like Eidolons though. It doesnt help that i've been pronouncing it as "Eeleodons". I don't quite know how I managed to get it so wrong.