So, for the past few months, we have been having issues with out upstairs neighbors.
They are 2 - 20 something girls, both with college educations, who are very "strange"
Anyway, we used to get along great. They used to come down here to use our phone and puter and what not, and we helped each other out with rides when one of our cars were down. We have always let them use our washer and dryer for the 1 1/2 ears they have lived here as long as they helped with the water bills. So far they gave us $40 and 2 gallons of milk (that the 1 girl got free when she was on WIC for a baby she didn't even keep).
Well, back a few months ago when the car wasn't running, I asked the one (the milk lady) if I could use their jumper cables and she ran up to ask her room mate. She came back down and apparently they were he roommate'* and she wasn't going to let us. :
So, since they did laundry for a year and a half for $30 and some milk (they gave us $10 more later) we stopped letting them use the washer and dryer. then they started playing their music at loud volumes coming right through our ceiling. This even happens at night after our girls are in bed. I have talked to them repeatedly and also the landlord, but nothing has changed. The cops have been called but they won't do anything unless it can be heard outside. Now after 4 months we are getting pretty fed up and are ready to fight back. What pushed us over the edge was when I cam home one day and the milk lady was getting her mail on the porch and saw me pull up. By the time I got inside she ran up and had the music on. (It hadn't been on all day, the wife was home) So we know they are doing it just to pi$$ off)That, and one day we came home and "Bite me" was written on our sidewalk with sidewalk chalk.
Well, since we couldn't take it anymore we went to the District Magistrate to press charges for harassment. Also, since I work for an Attorney, I had him send them a letter as well as a copy to the landlord.
But, I am wondering, is are we over reacting? I mean, the music is like "shake or walls" loud, just enough that we can hear it. I guess mainly it is the fact that we know they do it just to get on our nerves.

Yeah, not sure if it will hold up, but I think the fact that they continue despite the fact we have asked them to stop and the fact they did it as soon as I got home might help. If not, it was free to try. And, the police are the ones who recommended it.
And, i just remembered, last night when we ere on the couch watching tv, they were coming on the porch to go upstairs and the milk lady said to the other one, "let'* go upstairs and listen to music". They only said it cause they knew we'd hear them.

I don't think you are over reacting, but considering the situation I would rather move than possibly make things worse. Though maybe you can find something with the apartment that is a code violation that would cost the landlord a lot of money to fix, and just blackmail him into kicking out the girls or else you'll turn him in to the city.

We are thinking about moving. Of course, there are down sides to that.
A- We will be in a new home in 2 years or so and don't want to move 2x
B- Moving isn't fun or cheap
C- We aren't the ones who are causing problems, why should we?
D- (Kinda immature, maybe) We have lived here longer, the Landlord should be on our side.

As far as code violation, I think it'* close but not too bad. Although the City did just pass some kind of law that will require all apartments to be inspected so they may find something on their own.

All this over a set of jumper cables?

This is easy for me to say because I'm not close to the situation, but have you considered going upstairs and attempting to make peace with them? Tell 'em you got a beak because they wouldn't loan you the jumper cables when you desparately needed them, you felt slighted, they'd been using your washer pretty much for free, etc., etc.

If it were possible, I suggest this course of action. Takes a lot more effort on your part, but if it worked the result would be much more favorable than getting lawyers, landlords, cops involved. They'll think they "won", but in reality you'll be the winner when the animosity is gone.

Well, actually it'* over them. The jumper cable'* just made us feel slighted for all we did for them. The washer/dryer is just a small part. They used our phone and computer a lot. After the one had her baby she was down here almost every day with my wife. Also, we gave the milk girl a ride the one day when her car wouldn't start, and ours ended up breaking down and I ended up missing work. This is all before the jumper cables.
But, yeah, we have tried taking to them. They don;t listen. We had about a week of quiet and we thought all was well, we had said hi in passing and stuff, and they are back at it again out of no where.
I would be happy to sit and talk to them but they are to immature.

Well, some people are just jerks or, as you said, too immature to reason with. At least you tried.

Or they are doing something else in there and don't want you to hear...

^^ LOL Nah, I really think they are just immature jerks!!!
We have tried being nice to them, talking to them, they just don't get it.
Funny thing, one day my wife was so ticked that she went in the basement and threw the breaker. Pretty funny.
Remember guys, it'* not even about the noise as much as it is that they are purposely doing it to pi$$ us off. That'* what makes me so mad.