3 Krakinos(es?), supported by 2 Nevermores, one of which I pilot. No fighters (the fighters are severely undergunned for their size). Some auxiliary ships for cargo, flight decks and troop transport which I won't bother mentioning.
Invested most of my points into technology, which means that my ships are equipped with the highest amount of flux-related upgrades possible without compromising too much firepower. The rest went into logistics.
Even then, the buggers are incapable of venting flux at the right time, and spend most of the battle floating about with nearly-overloaded flux capacitors that they won't vent.
As for the ships I fight - just about every faction that's compatible with exerelin. The list is long, so I won't write it down here.
As for the ships I've used AGAINST the Blackrock - I found just about any capital ship to be capable of singlehandedly killing an entire Blackrock combine fleet (or whatever the name of the largest fleet of this faction is)
Sajuuk, Hildolfr, Core, Vatican, Behemoth etc etc etc
Engaging Blackrock fleets with an entire fleet is a joke, unfortunately.
Either the AI needs to be altered to vent more liberally (AKA, play the ships to their strengths), or the weapons need to generate less flux.
That, or make a dreadnought-sized ship that will be strong enough to hold on it's own in solo missions so that you don't have to rely on your fleet too much.