IPhone 5 or Nokia Lumia 900?

Tomorrow i'm making a new contract with AT&T but i'm stuck between these two phones (The iPhone 5 and the Nokia Lumia 900) Keep in mind that whichever phone i chose, i'm going to be stuck with it for the next 2 Years! So, i want the best choice.

As i said, i will be making the contract "TOMORROW" so i can't wait for the 920 to come out

It would be much appreciated if you could give an explanation to your choice.

Thanks.

Added (1). I also have the new iPod Touch with iOS 6 and stuff, so that's like an iPhone…
And just to be clear, no Android phones please.Me & Android don't get along very well -.

I have an iPhone 4S I've heard iPhone 5 sucks

IPhone cause I kinda feel like apple products are just superior and generally better and easier to use

Any new Phone can be a great compatitor for the other phone.
Iphone is very stable phone thats why everyone use it.
Android Phones have tons of Options and tricks.

your Questions is like Mac or Windows.

Get the lumia 900
it has an amazing build quality
the phone fits perfectly in your hand and it feels high end and premium in your hand
it has a 4.3" amoled screen with nokia clear black display
so that means colors and everything look amazing on it and that also means that you can see easily in direct sunlight so you don't have to higher the screen brightness
the camera is an 8 megapixle camera which takes amazing photos and videos
its carl zeiss which is a plus
and it also has the nokia added features like group shot, panorama shot and burst mode
what group shot allows you to do is to capture the perfect moment so for example if you are taking a photo of 2 people and they blink you will be able to rewind the time till when they were still smiling
battery life on the phone is very good and would easily get you through a full day of heavy use on a full charge
web browser on the phone is very good and fast
the phones os is amazing
everything runs fast and smooth on it with no lag
its just smooth and fast
overall the lumia 900 is an amazing device and you should get it
and since you already have an ipod touch with ios 6 their really is no need to get the iphone
hope i helped.
tell me what you decided to get
and if you got any question or need any help you can email me at spieleranswers@outlook.com

Why do you have to upgrade the second your contract is up? Hint… You don't.

The Lumia 900 is a great phone. For the price, there simply is NO BETTER VALUE out there. You will be able to get it for $49. An iPhone 5 will cost you significantly more… Probably $299 or so.

If budget is an issue, the Lumia 900 (or even an older iPhone 4S) is the way to go.
If budget is not an issue, wait until the end of October / early November when Windows Phone 8.

My personal opinion is that the iPhone is generally overpriced. Despite being brand new, the iPhone 5, for all practical purposes, is no better than the older Lumia 900. Of course, I'm not 'married' to the iPhone ecosystem.