What are the 10 most important MOSs in the Army?

40A!
Hah, J/K. Although I love my job, Functional Area 40 could go away tomorrow (all ~175 of us) and I think "The Army Goes Rolling Along" would still apply. There is a reason Functional Areas are not "accessions" Basic Branches.

1. The 13F, The one guy that knows the battle plan and scheme of maneuver. Keeps the 11 Series LT headed in the right direction as he a master of the map, and his radio talks to everyone on the battle field.
2. The 13D, He has his eyes on EVERY indirect fire weapon on the battlefield, he chats with the 13 F about bringing the pain with Naval, Air, Artillery and mortars to soften the target.
3. The 13B who sends the rain (Steel Rain) upon the enemy. HE to blow him away, WP to light up the enemies world and blind him with smoke, Mines to channel his movements. Special shells to make your enemy kick like a cockroach or glow in the dark.
4. The 36 (that's what they were in my day) commo folks that keep all these teams talking and easing the infantries path to victory.
5. The 15 Folks Those crazy young men in their flying machines, picking out what can not be seen and making it go away.
6. the 12 series guys, Clearing the way for the troops and digging holes in the ground so the boys looking at their objective so they can see and adjust their assault form a safe haven. Clearing the obstacles put in the way.
7. The 19s, tankers and scouts, riding the battlefield clearing off all the heavy stuff so the infantry can advance in safety.
8. The Medics, easing the boys pain and keeping them healthy and ready for their next big move.
9. The transport guys we called them 88Ms but they bring the food, ammo, Water an And haul off those thing that the boys don't need.
10. And finally the boys. Those Brothers that call themselves Infantry. For with all the miraculous Things all those before him can do, it is all done in support of the boys. The boys, the grunts, the infantryman is the only MOS, with his rifle and lowly bayonet, is the only one of all of these that stands on the ground that was taken and holds it. None but the infantry can stand on the objective and tell the enemy that over my dead body will you take it back.

Any Warrant Officer MOS...NCO's may be the back bone, but we're damn sure the brains of the outfit

91 Foxtrot small arms artillery repairer with out us the weapons wouldn't get fixed

If the MOS was not important, then it wouldn't be necessary! All are of most importance!

Ok It all depends on the mission but
Intelligence (because I need to know my enemy and what to fuck them up with.)
Artillery (because I need to put fear in them and minimize the damage to my troops)
Engineers (because I want to blow up that, that and that
Infantry (because we need to go kill them and finish the Job.)
The rest should just happily play there role because there last on my TLP's and priority of work.

As a former parachute rigger i believe it is one of the most mission critical jobs to an airborne unit

Does the Army have an equivalent of the Navy's first rule of combat?

Attention boys and girls - Artillery has long been known as the KING of battle. Napoleon gave artillery the sobriquet because of the devastating effects artillery advancements at that time were bringing to the battlefield Infantry is the QUEEN of battle. To help you remember we even have a Jody:

Up in the morning, outta the rack
Greeted at dawn with an early attack
First Sergeant rushes me off to chow
But I dont need it anyhow

Hail O' Hail O' Infantry
Queen of battle follow me
An airborne rangers life for me
O' nothing in this world is free

From a big bird in the sky
All will jump and some will die
Off to battle we will go
To live or die, hell I dont know

Hail O' Hail O' Infantry
Queen of battle follow me
An airborne rangers life for me
O' nothing in this world is free

Hmm, good question. I would all, but the ones I have best experience with are as follows based on gulf war. Those that drive A-10's, AC-130s, UH-60, AH-64, FA, medics, cooks, commo (31C at the time in Ratt rigs. I was LRS 11BPB6). I think all are equally important. Like a hand each finger is designed for a specific purpose and strength but combined together as a fist.