Alright. I'll throw in my selection too.
I'm going to say Eldars here. Though the Elerians get an honourable mention.
The Eldars: extremely long-lived, insane self-control, psychic, and crazy smart space elves. Their only con is the arrogance thing in my book, and there's surely SOME eldars who aren't. Well, there's the whole you-either-turn-into-a-crystal-or-get-your-soul-eaten-when-you-die thing, but whatever! Bonesinger ftw.
The Elerians: Telepathic, Omniscient race of blue skinned space elves. Pretty much like the above, only more aggressive and ruled by females. The first race of space elves I ever played, so yeah. You could always edit them to be something else, so I turned them into scientists. Yaay