I actually think there isn't really a "gold standard" for PvE. Most weapon types have their benefits and drawbacks, some are easier to use than others, some are more specialized etc.
As for "meta" I'd say there aren't many "Do's" but a few "Don'ts":
- avoid missiles bc of their low ammo reserve
- cannons (not multi) are rarely recommended. They suffer from low ammo and slow projectiles.
Gimballed Lasers are the easiest to use, followed by gimballed MCs. As previous posters have said, you strip shields with lasers and work on hulls with MCs, of which ideally one is corrosive. The big advantage of MCs over lasers is their low power usage and thermal load.
That said, personally I find MCs rather bland and look for other combos wherever possible.
Also, while gimballed weapons work best against small ships, they can make fighting bigger enemies (Medium and Large) rather tedious.
Railguns are imho the most difficult to use due to their charge-up delay. But a rail with Feedback Cascade works wonders on enemies with shield cell banks.
Frags are fun if you hit, but they only work at very close ranges so they aren't suitable for all ships.
But if any one weapon is something like a gold standard, it would have to be the Plasma Accelerator. Yes they have high power draw and thermal load, come in fixed only and normally have a low projectile speed. Again, trying to catch small targets with them is a pain.
BUT the magic word is "Absolute Damage" - PAs automatically pierce all armour, and 60% of their total damage bypasses all resistances of Hull or shield.
Also, they can be modded to use fuel as ammo which gives you much better endurance in general.
Moreover they have many worthwhile mods which makes them potentially very versatile.
And hitting stuff with them is FUN! XD
Recently I did a comparison between PAs and MCs, concerning effective damage. Superficially the MC may show a slightly better DPS value. But when you take Hardness and Resistance into account (not to mention damage falloff), the PA can end up being twice as effective as other weapons.