Do you mean designs as in hull templates, or as in weapons/defense/engine configurations?

Agreed. I usually try to aquire frigates asap (though not straight away as it takes a lot of time really early on) As Terran Alliance I generally research armour and missiles, as the evil civs seem to generally go for mass drivers and eventually I have my main conflict with them for some reason or other. AS for engines, I've found fleet warp bubbles can take care of that problem, as long as I can aquire some logistics skills.

However, in my last game I built up loads of fleets of a particular ship type, but then the Drengin learned how to defend against me and developed better weapons for their Super Dominator Corvettes, which I had previously torn apart with my frigate fleets and fleet suppot ships (using reinforced hull points and fleet warp bubbles) However, they could now roll out a lot of cheaper ships than mine that could match my fleets in numbers. So, would it be best to design my ships with reinforced hull points to counter all damage instead, as frigates can naturally take more damage?

Also, I can now build battlecruisers (large scale ships) I also have the option to build firgates which have pretty much the same firepower and defence (not including hp obviously)

So, Frigates or Battlecruisers?

I've always found on-type defenses to be more economical in the long run than more hit points.  Never gotten to have to face real end-game weapons, but in the frigate-phase of the game, defense rules.  

Frigates vs battlecruisers; what's your strategic problem?  Are you having trouble penetrating heavy enemy defenses to get to critical battlezones due to attrition of the attack force?  Then battlecruisers.  Are you having trouble getting enough ships in place to cover all your vulnerable planets and starbases?  Then frigates.  Are you twiddling your thumbs endlessly waiting for your forces to cross space to get to the battlefield?  Then you can put more engines on a battlecruiser and still have a viable warship.  

Answer depends on the problem.  

I do tend to put engines on Battlecruisers because as SCamb said, they can still be good warships even with bulky engines on them. However, coupling them with one of my fleet support ships is always nice as well. I've never got to massive hulls, (I will call them capital ships even though in Galactic Civ frigates up are classed as them.) Battleships then. My question is this: Is there any point getting them? When I start seeing the AI develop Battlecruisers of their own, should I go to capital ships?

lol, it was probably a problem when I was using fleets of 3 frigs against yor nightmare torps. I just quit that game.

Is anyone doing an AAR which will sort of give me a kind of guide to playing this game properly, and making good use of my research to produce a fleet to beat em? Every time I've tried normal difficulty so far I've just been overwhelmed by a fleet that either vastly outnumbers my own (that's usually our friend Kona) or is vastly superiorly technology (glances at the collective)

Started an AAR which pretty much shows you how I tend to play. If anyone would like to check it out that would be great!

Generally speaking ship design is, as you know, highly situational.  I will pass on commenting on the rock/paper/scissors analogy for the the beam/missile/driver weapons and shield/point/armor defense.  Instead, I will concentrate on the knowledge of how your weapon/defense values (not types) match up against your opponents ships.  I then use this info to gear the current research plans towards gaining the best time optimal combination and then get them into production ASAP. 

To put this into an example, if I need a minimum of 20 points of weapons with at least 12 points of defense for a given ship and I can only get up to 17 and 12 currently then I need to know what is the least research cost solution.  Sometimes it is in another level of weapons/defenses i.e. making them better or smaller but sometimes it is faster to research the next miniaturization tech or a engine tech (making it slightly smaller).  

I tend towards using larger ships in fleets so that it can survive multiple battles.  The old saw "what doesn't kill you make you stronger" is my motto.  In the mid-game I regularly have medium ships with 160+ hit points which isn't too shabby in my book.  I usually use the Super Ability of Warrior so that I get the first strike shot and use it as best I can.   

IMHO

The problem with zero-engine ships is that they take a lonnng time to get anywhere when playing the larger galaxy settings.  That is, such are fine for defenders, say of mining starbases, but zero-engine ships may not be able to respond to an oncoming fleet heading for some target not nearby.

Of course, one could always build a mega-slingshot spot, but that is very expensive.

Several Military Starbases fitted out with speed-enhancing modules. The best spot for them is the corner of a sector. This way, you can build 16 of them close by, increasing the speed of your ships by 32+.

I normally go with a combo of beam and missile weapons with a combo of shields and armour for defence until ecms become smaller or a enemy is using missiles only.

This is at beginning of a game and for basic ships toget you going:

Techs needed:

Titanium armor 3,basic miniturisation,general life support,laser V,stinger IV,Mass driver 4?,superior deflectors,(logistics at any level you want)

tiny Hulls: 1x impulse engine,1x general life support,1x either beam or mass weapon?

small hulls: 1x impulse engine,1x gen life support,1x beam/mass/miss weapon and 1x armor or deflector if using beam or mass weapons as missile will take too much room.

Medium hulls I tend to have between 3-4 types of frigates all with 1x impulse engine,1x gen life,1x deflectors,1x armor and with the weapons I do a all beam (4x laser V) a all missile (2x stinger IV) a railgun frigate (3x mass driver) and a combo frig (2x laser V + 1x stinger V)

Large hulls I tend to do 3 types 1 all beam,1 all missile,1 all railgun

Huge hulls I tend to do combos either beam and missile or railgun and missile or all missile I also use huge hulls to put warp bubbles and bonus modules on.

As for design ideas for templates checkout ship designs 2007 through to 2012 or google images of gal civ 2 ships or mods