All of them. But that is just my prefered play style. Although I have not played very many games (less then a dozen) so my advice might not, well probly is not the best. But so far this is what I have found.
Choke points. examine the map before you start. Plan on making about 3 rushes, one from mk 1-2 AIP, One from 2-3 AIP, and one of 3-4 AIP. And plan on taking a breather and rebuilding before you break the threshold. So the way you want to end your rushes is with a section of space emptied out. If you get one whole area cleared, you dont have to defend it.
The snake map is perfect for this, But I have done it on other maps too, the thing is to just clear one line on the map at a time. Try to clear the big open planets all at the same time, to get to the planet that only has two connects to it.
Choke points are easy to defend. Although you can only have about 3 self sustaining choke points at a time. when when you are planning out your rushes, plan them out to only have 3 defense locations. If you go more your spreading your forces out to much and you will get overrun. Your defenses should be at the wormhole that is going to attack you. (if only one place is going to attack), or the place that will leave if multiple wormholes will attack. Although it is always easier to defend an incoming wormhole then an outgooing. Why you might ask. Lighting turrets. The AI could be sending 20,000 ships at you. And with lighting turrets galor, They will take out the majority of those ships. at the very least damage all of them so it is easy for your other defenses to take them out.
As for which turrets to build. Basic are the most cost effective, early game when there are not many ships that attack you, these are the ones you want. The missle one and the MLRS ( think thats the other two), they are good, exspecialy the one that is good against bombers becouse it picks up slack where the other ones leave off. And basicaly by the time you are building these ones in mass you want a balance net of them all. Once the attacking waves are in the couple of hundred, you are going to wanting lighting turrets, they are just good at taking stuff out in mass. Once all those start toget used up I will mix stuff in like laser turrets and the such. I dont really mess with sniper or spider, maybe on a leaving wormhole instead of an incoming. And like I have said idealy you want all your defenses on the incoming wormhole, I like to place them in between the two wormholes, where the attack radius is just covering the incoming wormhole. And place a forcefield over the exiting wormhole so if they do manage to get past my defensive line they cant leave the planet.
The reason for this is as soon as they come to the planet, they are being attacked, They usualy make a V-line for the command station. (unless there is anouther target more critical, then adjust acordenly). so they recieve shots for the entire range of the turret giving maximum potential. To help this out I also place allot of tractor beams in these area's. to keep them there so my turrets can do even more damage. As to the amout of tractor beams, I create lines of them. Enough to keep any attacking fleet in the line of fire with a bit to spare.
The next important part is to attack quickly. Becouse of this I favor captial ships for research. They can take a real beating without dieing and having tobe replaced. I also like shreaders, for the simple fact you dont have to rebuild them, they rebuild thereselfs. (tech one does the best job of this). When I warp my fleet in I like to keep them all grouped togeather for the initial attack (except for the raid starships). I have raid ships move out and attack the command station first, then the warp gate too since they are there. If an Ion cannon is in the system this is my next target, Followed by speacial forces guard posts, then regular guard posts. By this time most of the forces should be destroyed in the system, I can then start moving my main force towards the next wormhole while my raiders clear the rest of the system. (also during this whole time I am doing the N+9 to select any ship that is less then 66 percent health and ordering them back to my nearest planet for repairs. By the time my fleet reaches the next worm hole the raiders will have cleared out the rest of any defenses, and I can then warp to the next planet and continue.
If you do this all fast enough you can acualy be attacking the next planet before they have time to reinforce it making it ripe for the picking. I did a 20 planet rush using this method recently, And the only reason I had to take pause was becouse I was attacking a home world.
I know this is not how the developer team intended the game to be played, But I think with the recent changes they have made to the game this stratagy is even more viable. Once you have a good chunk of planets your resource income is so great, your attacks turn into more of a zerging. With 3500 income each of metal and crystal, you can have all your enginers assisting your space ports to keep your fleet at max cap constantly. And this is going tobe needed, becouse once you get down to the last few planets the AI reinforments will come so fast, you will have to take out the command stations quickly.
Once the AI reaches max capacity, you are going to have two choices on how to procede, Either a brut force crawl, where you have everything attacking (even going in and building turrets and repair platforms in the system you are attacking). Or Missle strikes. EMP's stack, And you can build them fast enough to increase the time. which you will need on the IV planets and core planets towards the end. It wont disable everything, but just enough to turn the battle in your favor.