What's your favourite Weapon/System/Sub-System?

[Aegis]

Weapon: Ion beam II - hands down. Autofire this on shields and every battle is easymode, use whatever else you want afterword, drones, firebeam, pike, laser, boarding... doesn't matter. Gives you copmlete freedom of choice for your build. Further, since the rate of fire is disgustingly good you max your weapons skill quickly.

System: Engines. Less expensive than shields if you count the inital level. FTL speed boost means you hit more nodes per sector - which is critical. Evasion - espeically late game - is superior when dealing with massed projectiles and bombs. Burst 5? No sweat if you dodge 4 of them.

Subsystem: Doors. Max them out. They're cheap, and most importantly, provide the superior solution (and the most time) for handling the two most annoying things to deal with in combat: fire and boarding parties. If you vent your ship in an effort to force those intruders to fight in your medbay, but they break your door controls along the way you're in for a bad day.

[Mauzel]

Weapons: Burst Laser II, only 2 power for 3 shots, good for bringing down any shield. I usually aim for a pair of them, coupled with a good 4 power damaging weapon, like the Glaive Beam.
Another fun pair is 2x Ion Burst II 1x Fire Beam, the 2x Ions can keep even a 4 shielded ship from shielding up, and a single fire beam can ignite up to 8 blocks in one shot. (Not to mention to be without the cost of missile like the fire bomb) By the second firing, the ship usually will burn to its death, as AI still seems to prioritize medbay, weapons, and shields, resulting in the O2 completely being destroyed, not that they can put out the fire sufficiently fast enough before another beam approaches.

By the third shot of the fire beam, it becomes very pretty.

Drones: Hull Repair drone is nearly a must for any ship I play, 2 power and can repair my ship at the cost of the ne'er-to-be-used drone stash on a premium. Especially useful in hostile sectors, ships primarily focused on evading/cloaking, or simply to save trips to a previous store for repair. In close second is the Def Drone I, 2 power for a 90% defense against enemy rockets, for any ship that have strong shields but not much dodge for the missiles.

Systems: Offensive, either Weapons max with 2 drone, (For my hull repairs or missile def) or Drone max with 2 weapon. (For my bomb or missile to counter enemy shield/drone) Defensive, either engine max with 4 shield, or shield max with 4 engine.

Subsystems: Doors, hands down.

[Antesignanus]

Glaive Beam is freaking boss. Deals 3 damage per hit and can semi-pierce through 2 shields. That along with some lasers make the game pretty easy. I'll usually settle for a Halberd though. I also enjoy the maxed out Artillery Beam.

[Vind]

Defense drone I as it targets only missiles and meteors.Ion pulse II as it lock down 2 shield levels with quick firing. Blast doors for obvious reasons. Shields as you can beat final boss even with 3 lvl of them.

[draeath]

Ion II is my favorite. Extra credit if you find firebombs or the fire laser.

Pound down the shields, pound down the O2 generator... repeat. Slow death!

[imaginary_num6er]

Weapon Primer Augmentation.

Your strategy changes entirely whether you have this or not and suddenly, those 3+ Power Rating weapons don't look that bad any more. The alpha strike looks awesome too.