For species my choice is Salrilian. Their ships function superbly in fleet combination and the AI plays them with deadly efficiencey.
As far as ships go, it's a tie. Neither of them are Salrilian though. The first is the ever speedy, ever confusing Aud cruiser. You can take out just about anything with that agility. The second is the Human HVD which has the best maneuverability of all human ships and quite possibley all HVD's, and it has some serious firepower.
I can't understand though, why everyone always picks a carrier. The Sal carrier to be exact. As a fleet ship they're the best you can find for a heavy assult, but as far as piloting goes, it steers like a shopping cart, and accelerates like a fat guy on a pair of rollerbladers with nothing but the power of a light breeze behind him. Perhaps it's the brute force. I preffer finesse.
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Throughout their history these "unenlightened" beings have continually opposed and fought abuses of power wrought by their own bretheren. We, as the prophets would do well to learn from these Humans.
-Final statement of the Salrilian reformist Sirthis shortly before his execution.