I choose... Not you?

[Mercen-X]

Pretty sure I've played as all of them.

QFT

Though I would usually play as Fighter/Warrior, Thief/Ninja, Red Mage, straggler.

[ReloadPsi]

I used the Black Mage the least because it becomes horribly obsolete once you find items that cast the level 2 spells on all enemies for free.

Actually it becomes horribly obsolete earlier than that if you use a Red Mage. The Red Mage is the best and most broken class by far in the NES version, and this is coming from someone who hates the colour red.

The BM in FF1 is completely useless as the RM can do most of what it can do, and by the time the BM has enough MP to cast its spells more than three or four times they're now pointless because your physical attackers will do more damage with melee damage. By the time you can afford the level 2 attacks, the Red Mage's level will be high enough to cast them. Sure, RM can't cast Flare/Nuke/whatever but by the time you can get that spell you don't even need it any more.