One of everything!
OK, well for a realistic suggestion...
Get two squads of People's Volunteers, an Eradicator Death Droid, 4 Attillas and a Scorpion.
That will give you "the heavy hitters" portion of the Cyber force list. .
One sqad of Mirromen, Dr. Dianna, Machinator Mk II's, Cyril Dent, and a TA 6500, and a handful of Enhanced Curassiers would be the next step to complete the force.
Cyber has a well balanced army, and having at least one squad of each unit type will give you a lot of options depending on the scenario you want to play. Plus, they just look cool!