Who coincidentally (or perhaps not), happens to use Defilers.
Not biased at all here.
Defilers are exceptional against Terran, but still useful in the other two matchups.
Dark Swarm affects every Terran unit except for the Firebat, and the splash damage from Siege Tanks. Firebats are easily massacred by the time you have Defilers, and Siege Tanks damage is still significantly reduced, and can be nullified nearly completely by burrowing (damage is reduced to 1). Protoss have a significant amount of ranged also, although things like storm and reavers nullify this somewhat. Zerg, if it gets to this level, have quite a bit of Mutalisks, Lurkers and Hydralisks.
Plague is great for weakening groups of enemies, or for destroying Terran buildings in the absence of repairs, useful against everything from massed Science Vessels, to Dragoons to stacked Mutalisks. Combine this with the ability to instantly refill energy by consuming readily available Zerglings, and you have a winning combination.
Ghosts, on the other hand, are much more situational. They're energy has to be carefully rationed between cloak and lockdown (which of course doesn't work on biological units, e.g. all of Zerg), and nukes are so hard to land against an observant opponent as to be nearly irrelevant.
Are you a Zerg player?
I don't have time right now but tomorrow I will reply to this since I have plenty to say.
Age of Empires II has the best combo of playability and "features" IMO. some of the newer games have gotten so feature loaded that you can't finish a game in under 24 hours.... Age of Empire II games can be REAL quick with the right strategies...