What three characters do you use?

Cloud, Tifa, Yuffie

Yuffie in Fury status, Clear Tranquil, and Counter Attack (sometimes Cover Materia)=Almost unbeatable.

Before Aerith's death:
Cloud
Aerith (weak physically but useful limit breaks & magic stats)
Yuffie / Barret

Random battles:
Not definite. Cloud is a must nonetheless. :D

Boss fights:
Cloud
Yuffie (as a medic)
Barret (though he has extremely low agility but i overcome that by morphing 1 of the monsters in the sunkern plane (i cant recall) into speed plus. If i'm not mistaken the one that uses 'tentacle' attack..)

The setup I usually use is Cloud , Cid , Tifa

During the first part of the game, I use Cloud, Tifa, and Aeris (to get all of Aeris's Limit Breaks)

After (SPOILER)Aeris dies, I use Cloud, Tifa, and Vincent.

The first time I went through the game, I used Cloud, Tifa and Vincent.

Since then I've used everyone at least once to go through the game. But most recently I used Cloud, Cid and Yuffie.

Cloud Cid and Tifa is the best party for limits.
Yuffie is fast as mentioned above. I usually rotate bewteen these guys & Vincent.

Cloud vincent and nanaki

cloud cid tifa

Cloud, Tifa and Cid/Vincent/Yuffie

Depends on the situation. But I usually use Cloud (Green Mage), RedXIII (Red Mage) and Tifa. (Monk)

Cloud, Vincent and RedXIII. If i couldve kicked Cloud then i would have cid or tifa

For me it used to always be Cloud, Cid, and Red XIII for years.

However, I sometimes use Barret in place of Red XIII now because of his limit breaks.

I sometimes use Yuffie from time to time also.

I very rarely use Vincent and Tifa, although I don't mind them.

I never use Cait Sith, don't like him much.

I usually give every character a chance though, and spend time training certain characters for when they are needed in the game - for example, today I trained Barret just before batteling Dyne. I killed Dyne with 1 hit, which was Barret's Ungarmax limit (technically multiple hits, but one command).

I use them all pretty much equally.

Cloud, Barret and Yuffie.

I haven't played in a long time but the few times that I went through it I always used Cloud, Nanaki and Cid until Vincent then Cloud, Nanaki and Vincent.

If I was to go through it again I'd try use them all equally.