the armor JR is also, not an aluminium case, it has the front bezel aluminium, but apart from that it's Steel.
the armor JR and tsunami are both mid ATX and both steel/aluminium.
According to the Thermaltake site, the Armor Jr. and the Tsunami are ALL Aluminum. I personally recently bought the Tsunami Dream in Silver with the window and I LOVE it. It is stylish and well made.
The question though is how much room do you need? Do you truly need a Full tower or are you able to get away with the Mid Tower? What all are you putting in the case?
Mplich, your avvie... Hmmmm... the more commonly used equation to find power is P=IV, or at least us EE's commit this to our memory of electrical's holy laws...
The Armor is a good case, and I can see the Armor JR about the same, however, I would only get the armor if it's possible to get the 25cm side fan... which I don't think they make for the JR.
The Tsunami is a great case, I would get it if you're not planning to stick your computer chock-full of HDD's.
I like the shark's looks, but when I saw the design I knew that dust would come in from the sides. You can always add your own dust filters, since those are relatively cheap, but that will be your choice.
Actually I don't think the Shark looks better but that's personnal preference. Is there a reason you're looking at the full tower Shark but not the full tower Armor? I have the Tsunami and the Armor (full tower) and I'd choose the Armor full tower over any of your other choices. You don't have to get the 25cm fan either, I moded my side window to add a 120mm fan and it works great.