While we're on the topic of branches; I have a few questions as well. I enjoy working with people and technology and I plan to major in electrical engineering. I know it's a little early to be thinking about branches, but from what I've read, signal, MI, and ADA have piqued my interests. What are your honest opinions on those branches?
Here is my thought on branching:
This is my opinion. It's free and worth every penny. If you truly want to be a part of what the Army is about, you need to be in a branch that will be the main effort of the fight. If your branch isn't going to be in the main effort paragraph of the Scheme of Maneuver portion of the OPORD, you're not going to really experience the business end of the Army. That means, generally, you would want to be in the maneuver, fires, and effects branches (what we used to consider Combat Arms). There are some caveats to that. Generally speaking, I urge all males to consider Aviation, Infantry, Armor, Engineers, and to a lesser extent, Field Artillery.
The point is that decisive actions are not planned around the Signal Corps, or MI, or ADA, or Finance, etc. The meat & potatoes of being an Army officer is being a leader of warfighters in close combat. Support branches are just that...support. That's where you tend to find your type-A go-getters. In simple terms, think of this way: when you were a kid and you played Cops & Robbers, did you ever say "I'll volunteer to be the desk sergeant!" No, you did not. You volunteered to be the cop. Or the robber.
As for the branches you mentioned...
MI: You will largely experience war through your email inbox. You won't leave protected areas much, if at all. The result is that you'll spend much of your time analyzing products produced by other intel geeks and turning them into usable products for your unit. Get to know powerpoint, because it will be 90% of your career.
ADA: Don't even consider that branch. They're a branch in search of meaning and relevance. The days of humping Stingers alongside the infantry are gone. It's all Patriot Missile focused now, and that's the definition of "in the rear with the gear."
Signal: In this day and age, you'll spend almost all your time setting up computer networks and filling radios. The best a SIGO can hope for is to not get yelled at. If everything is working, you'll never get a pat on the back. The second someone can't talk or can't print, you're the first guy they call a you-know-what.
Some folks will likely get bent out of shape about this, but this is how I see it. Is the support side crucial? Of course. Bad logistics and bad commo will ruin a mission faster than anything. But it's still support. Who got a handshake from the President? The guys who flew the shooters to Bin Laden's house and the guys who shot him. Not the Signal Officer who loaded their radios with the right crypto. Not the logisticians who secured all their ammo and fuel. That's not my way of saying you should be a glory-chaser, but those guys are our heroes for a reason.
If you want to be an officer in a position of consequence and see what the Army's about, then you want to be in those "operations" branches. ADA, Chem, Signal, MPs...support is support.
Maybe that's what you want, but the vast majority of officers I've met in those branches wished for combat arms and didn't get it. So consider that for whatever you think it's worth.
Again, support functions are important. I mean, life would be downright unlivable without indoor plumbing. That doesn't make me want to be a plumber, though.