Ziggurat, Radiant, five to seven Dooms (for multiple fights), two or three Harbingers. Do not know if Phantoms count as combat ships, I bring about five of them to raid pinata planets (for supplies or drugs) to the ground. Sometimes, I bring Paragon too.
I want to bring backup ships in case my primary ships die or run out of CR. Ziggurat and Radiant are hangar queens, down to malfunctions after one fight. If I kill a triple Radiant Ordos (with chain Dooms or something), several ships will be damaged too much to chain-battle the next Ordos out of the mob nearby. If I am not hunting Ordos, I can probably cut the ships down to Ziggurat, Radiant, two or three Dooms, and a Harbinger.
If the enemy brings big fleet, I want a big fleet too!
Without Tech 10, I cannot do some of the cheese as well as a Tech 10 fleet. Special Modifications is really powerful for some ships.
I took Automated Ships instead of Spec.Mods because I did not want to take any permanent skills, and watching overpowered Radiant wreck things like an SNK boss would in a fighting game is fun.
I2 isn't logistics and if you want combat bonuses there is a tree for it.
Which I take too, which leaves Leadership the odd tree out, and I highly resent the game pushing me to take Leadership skills (specifically Wolfpack Tactics) because fleet needs frigates unless I abuse phase ships. (I guess I could use Furies, but I got phase ships by the time I could build unlimited Furies.)
Last release, the Combat skill I took first was Combat Endurance (or maybe it was Helmsmanship and Evasive Maneuvers for mobility boosts), which is now in Industry as Reliability Engineering.