Recommended Weapon Research Order
Xcom EU
Start off with Laser Weapons, up to Laser Rifle. No questions here, since Laser Rifle is so ridiculously powerful, it renders all AP weapons obsolete. It is better than the Plasma Pistol and even seems to beat the Plasma Rifle as an overall weapon.
I get Personal Armor at this point. Firstly for the higher armor values, secondly, the immunity to fire (and smoke) makes for some very interesting tactical choices...
Small Launcher and Stun Bombs are often overlooked in favor of more lethal weapons, but IMHO, these should be researched before Plasma... IF you happen to scavenge any. Their huge nonlethal AOE damage makes them incredibly good for storming UFOs, and they're better than the stun rod. This also makes the next step a lot easier:
PSI. Get this ASAP. This will depend a lot on luck and sacrifices, but anything is worth getting early access to Psi.
I usually skip straight to Heavy Plasmas, but that's because I play on Superhuman, so by this point they're common enough that they practically grow on trees.
Blaster Bombs, if I can get them.
Jasonred 07:11, 7 April 2009 (EDT)
TFTD
There is an ongoing discussion whether to follow the Gauss path immediately, or just jump straight to sonics. There are pros and cons either way.
The research path is much convulated in TFTD, so I often need to begin my Aqua Plastic Armor and MC research at this point.
Thermal Shok Launchers ASAP... you can defeat just about any scenario using only Thermal Shok + Gas Cannon. Makes captures and killing Lobstermen a lot easier.
Rush for Displacer/Sonic. This requires me to research Sonic Cannon (New Fighter Flying Sub). These things are SO much better here than Hovertank/Plasma back in Xcom. They are WELL worth using up 4 soldier slots, if you don't have uber MC. Sonic Cannon also needed for Sonic Oscillator... which are often REALLY needed, to shoot down those ships trying to perform Alien Surface Attacks...
PWT Launcher and ammo. Ridiculously powerful weapon, as always. The aliens will use them on you without mercy, so it's best to keep a level playing field.
It seems best to research Drills next, if available... Drills ROCK in this game.
Sadly, Gauss is lumped together with all my other "completing the UFOpedia" research entries. It's not a bad weapon, really, just that TFTD can be brutal on Superhuman and I can't afford to waste research time on non-vital research paths.
Jasonred 07:11, 7 April 2009 (EDT)
Pretty much agree with all that, except I do tend to research Gauss - the Gauss Pistol comes quickly and is a huge improvement, as is the Gauss Rifle. The Heavy Gauss has some advantages and brings you closer to the economic advantages of Gauss Cannon manufacturing, but before that point there will be other more promising avenues to persue such as Sonics. Arguably, switch from Gauss research to Sonic research as soon as you have an example of a Sonic Pistol in your hands.
One point I would add though is to research Sonic Pulsers asap. This is such an easy win, as it does not take long and you don't have to research the clip. Plus, they are always relatively abundant to scavenge from the battlefield. With Sonic Pulsers you can tackle almost any enemy, and you can have them very soon in the game.
Spike 13:46, 4 August 2009 (EDT)
Note that unlike in EU/UFO, the Sonic Pistol is a very useful weapon and the Sonic Cannon has severe drawbacks making it pretty much solely a sniper rifle. You have to research both (and the Sonic-Blasta Rifle) to get the Sonic Oscillator, but consider the Sonic Pistol first. Magic9mushroom 05:21, 5 August 2009 (EDT)