Well, do you have more information of this kind? I'd need those. I play the game for a long time. Nevertheless, I think at this time I'd lose against nearly everyone of you.
Here you go. This is part of the multiplayer strategy guide I have - it's not all that relevant to single-player because the AI is too stupid to use ships effectively (just spam LRF or bombers to kill AI).
Each ship has an armor type and a weapon type. Different weapon types are more effective on different armor types. This system is why fighters decimate bombers, why bombers decimate heavy cruisers, why heavy cruisers decimate LRF, and why LRF decimate light frigates. Etc. A good player will know the damage types spreadsheet like the back of their hand. Here is a link to a recent damage types spreadsheet, courtesy of SithLordAJ from the Sins forums:
http://www.mediafire.com/?l4ojbcci0254ar9
You don't need to memorize it necessarily, but you need to understand how to read it to see which ships counter what.
Scouts are good at killing other scouts, colony frigates, siege frigates, and LRF, but nothing else. Advent scouts are particularly good at this due to their high durability. But you usually shouldn't be building many scouts past the first few minutes of the game. To counter scouts, use anything other than LRF: preferably, use flak.
LF are good at killing flak, but that's about it. However, LF are very weak against enemy LRF. In the beginning of the game, you probably shouldn't build more than a couple LF at once, unless the enemy has few or no LRF, which is rare. Exception: Due to the subpar and logistics-expensive Advent LRF (Illuminator), Advent players often build lots of Disciples and Seekers early in the game instead of beelining for LRF.
LRF are the general-purpose offensive combat unit. Early-game, they are the best for countering enemy LF and enemy capital ships, but are also relatively effective at killing structures (especially Orkuluses). Unless you're Advent, you should probably have at least 60 supply worth of LRF built at any time, so that you can fight off enemy capital ships: if the enemy is Vasari, he will probably try to SB your worlds, so it would be nice for you to build a lot more LRF. To counter LRF, build a large number of flak, preferably, or if that's not possible, then build more LRF of your own, or build scouts.
Flak are good at defending against enemy strike craft and light-armor frigates like LRF and scouts. They are pretty cheap and have large hulls - don't be afraid to build 20 or more of them if the enemy is spamming tons of LRF. Flak also have very high listed DPS, but are most effective when all 4 of their banks get to fire (front, back, and sides). Maneuver them into the center of enemy LRF packs for them to do the most damage. They have to be micromanaged a lot - they should also probably be put in Hold Position so they don't go chasing after enemy strike craft halfway across the gravity well. However, each bank doesn't do much damage, so they're more effective if you can 30 or more of them at once. Trying to counter flak is annoying: the best ship to use to counter it is the vulnurable LF, and even then it takes a whole lot of shots to make a dent in the flak's armor.
Sometimes it's best to simply ignore enemy flak and attack enemy planets with your own capital ships and heavier armor ships of your own (flak do next to no damage against ships with medium or heavy armor).
Later in the game when more ships start appearing, things get even more complicated - look at the spreadsheet to see what's best against what.