Materias that are a must get...

[Sword]

Ultima=Counter

That needs to be Magic Counter.

Nope it's just called "counter". It can be combined with summon and command materia too.

And yeah Health naturally you need to AQUIRE all the ultimas first. I was just using it as an example.

[TheSpoonyBard]

Nope it's just called "counter". It can be combined with summon and command materia too.

Counter only works when paired with Command (yellow) materia. Magic Counter only works when paired with Magic (green) or Summon (red) materia.

[Northcrest]

Are u able to get the Choco/Mog Materia in disk 3?

[Trisdyn]

Har har. I scoff at these pathetic newb combos. (Just kidding, don't flame me.)

Let me fish out my FF7 strategy guide. (Once again, please don't flame me.)

Top 5 absolute needed Materia in Final Fantasy 7.

1. Knights of the Round
This is a given. This is an absolute need to destroy any boss and WEAPON in FF. Coupled with W-summon and select other combinations, you will surely make your boss fights much easier. (119,988 points of damage if your INT is high enough.)

2.X Summon/Quad Magic
239,976 points of damage in one turn, coupled with KotR. Need I say more? 479,952 points of damage with Quad magic.

3.Mime
Allows your party member to copy the last action. So, if they have a lot of int, 359,964 points of damage! Oh my god! What happens if your last party member also has mime!? 479,952 points of damage! OMFG! And Quad magic? 719,928!!!!

4.Final Attack
When you die, you get to do something. Obviously this would be coupled with Revive.

5.Either Quad-Magic + Ultima or Mega All + Shield.
If you have someone with int, Quad will do 1/3 damage of KotR. Or, you can focus on the defensive and get Shield... from the final dungeon.

Now some killer combinations.

Sneak Attack - Knights of the Round
Begin the fight by casting KotR. Mime em' to hell. (Less effective, as you cannot couple this with W Summon or Mime)

Cover, Counter Attack, Counter Attack, [Command] Counter-Deathblow
Cover for other characters and immediately counters three times, finishing with Deathblow. Not as effective as causing damage as the other alternatives, but still nice.

Pre-emptive, Sneak Attack - KotR, HP<-->MP
Get the first strike and cast KotR. Characters that have the HP<-->MP materia will be able to continually cast with no rest.

Enjoy.

(Note: This just in! Other party members can mime W Summon, making them cast 2 times as well! But Quad magic cannot be mimed. And no, you cannot manipulate the materia to junction W Summon AND Quad to cast KotR eight times in a row.)

Boy, let me tell you, after seeing all those KotR animations, it gets preeety repetitive. But you can find that out for yourself

[sir helix]

x4=all is the best

[ReloadPsi]

Magic Counter-Restore (Have to be mastered)
Final Attack-Revive (Have to be mastered, helps if you've more than one instance of this combo too)
Double Cut, helps if 4x-Cut is available
W-Item (use a Turbo Ether and an X-Potion in the same turn; they become ridiculously easy to find later on)

Stick those on a Mystile, give the character any weapon you please and they can solo absolutely any boss. I spent so long fighting Ruby Weapon with that combo that he actually ran out of MP, but I defeated him with little trouble, other than my laptop's battery nearly running out. I've not tried it on Emerald, which I imagine would be a damn sight harder, but it's gotta be worth a try, right?

[TheSpoonyBard]

1. Knights of the Round
This is a given. This is an absolute need to destroy any boss and WEAPON in FF.

It's absolutely not necessary, but does make things a little easier.

2.X Summon/Quad Magic
239,976 points of damage in one turn, coupled with KotR. Need I say more? 479,952 points of damage with Quad magic.

KotR does not work with Quad Magic. The most you can do with it is W-Summon it.

4.Final Attack
When you die, you get to do something. Obviously this would be coupled with Revive.

I find Phoenix works better.

Mega All + Shield.

Doesn't work. Shield is one of a few spells that I believe are single target only.

But Quad magic cannot be mimed.

Yes it can.

And no, you cannot manipulate the materia to junction W Summon AND Quad to cast KotR eight times in a row.)

True, you can't do this with KotR, but any other magic/summon works fine with W-Magic/Summon and Quad Magic.

[Takara]

1. Knights of the Round
This is a given. This is an absolute need to destroy any boss and WEAPON in FF. Coupled with W-summon and select other combinations, you will surely make your boss fights much easier. (119,988 points of damage if your INT is high enough.)

HAHAHAHAHAHAHAHAHAHAHA no. It is not absolutely necessary to beat any boss or weapon. Useful, yes, but not necessary.

[Bart's Friend Milhouse]

Trisdyn, maybe you should play the game a little bit more before attempting to give anybody else advice.

I believe you can complete the game well and good with only a very basic list of materia. Restore is almost certainly a must-get. The Wutai side-quest would further cement this idea

[Peter_20]

These are the only Materias that I think are pretty much required:

Restore
Heal
Revive
Lightning
All