Since being a superbrain seems about as attractive as choosing between life as a sea sponge or a pot plant, one option is to avoid the whole brain thing and leap straight to  pure energy.  For some reason a lot of people regard this as  extremely cool, though they never consider what being pure energy means.  For one thing, if there's no brain, what do you do your thinking with?  Energy is like water running through a pipe.  It doesn't have any ability to alter itself unless something channels, portions or otherwise acts on it.  That's why energy is so great for sending information.  Streams of photons may degrade, but they don't spontaneously edit your messages en route from transmitter to receiver.  Also, energy has this nasty habit of not staying in one place.  It spreads out at the speed of light, so the moment you achieve energy being-hood you're already halfway to the Moon.  "I am FOOMMARGH!  Fear me and... Oh, bugger!"

Arthur C Clarke

Despite these little setbacks, Sir Arthur C. Clarke considered energy beinginess for mankind in his 1953 novel Childhood's End.  Just when man is on the verge of conquering space up pop an armada of flying saucers the size of cities that put the kibosh on the whole thing.  The aliens, which rather pointedly resembled devils (oh, the irony!), impose a golden age of Enlightenment and Reason that would have done Voltaire's heart good, but it turns out that it's just a booby prize for mankind, as the human race is about to spontaneously evolve into a race of superbeings with a single collective mind that will merge with a sort of galactic supermind and the devil aliens are along to make sure it all goes smoothly.  "Sorry about your civilisation and all your achievements being a pointless waste of time, chaps.  Can't be helped.  Toodles!"  Mind you, the fact that this next great leap in human evolution seems utterly devoid of individuality, personality, or anything like basic human compassion makes one wonder if there isn't a wee bit of power worship going on here.

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