As much as I hate to say it (i'm about to argue against my fav char.), don't spend to much time on Aerith, you know why...
And vincent is a little too weak (not counting his awesome limit breaks)

I would stick with Cloud, Cid, & Barret... Those are your doomsday guys if you like physical attacks.

For a magic party though... Cloud, Red XIII/Nanaki, & Cait Sith (even though I hate him)


Don't blame me if you get totally burned, though...