Which Case/PSU should I go for??

i heard that the 180 case was pretty quiet and runs cool,also i have the neo 550 he psu and its running my rig no problem for the last year.so that would be my recommendation.if you haven't bought already

My choice would be the P180 case. As for your power supply, if you're going to have a 8800 card, you need to think about at least having 700wt. Depending on your total amount of hardware, and whether or not you'll be overclocking, 750-850wt might be better.

In my opinion, unless you're otherwise running a barebones, non-overclocked pc, either the 550 or 600wt psu's that you listed won't do the job with the 8800 card.

Well I think the Zalman and the Antec should be able to support the GTS. Can you list the amps or give me a link to the PSUs I will be able to tell you for sure.

If this is the Zalman PSU I highly recommend you read that review.

the 550 i have works fine with 1 8800 gts card overclocked a little. however i will say if you plan on 2 cards get a bigger psu,i just installed another 8800 gts card for sli and im having some trouble.it works but i think its throttling down because my 3d mark score only went up a few hundred and when i try to overclock it shuts the system down.going shopping for a new psu

I have built with both the P180 and the P150. The P150 is my favorite. The P180 is larger, and is awkward to work with, particularly with installing the PSU. They both are quiet in a deskside environment with the stock fans on low. The P150 has (3) 5 1/2 external drive bays, of which two have stealth doors. The doors can be removed if you don't like them, but they worked for me and they are supposed to help keep things quiet. The 430w power supply that comes with it is pretty good. I was prepared to change it out, but it worked well with an intel P4 3.8 and a 7800GT.
I am currently using the Antec solo which is the same case as the P150 except it is cheaper because it does not include the PSU. It comes in black instead of white, and does not have the stealth doors. I used a Seasonic 550E with a 8800gts and a e6600, and have no problems.

I have no doubt that the 550-600wt psu's, particularly the Zalman, can power the machine, but it depends on how much hardware is attached, how much the overclock is, and to a large extent, if SLI is used.

I'm admittedly influenced my own machine which has a lot of stuff in it and pulls about 640wt on my present gpu, much less what the future DX10 card will demand. Looking to the future, if I have to buy a psu, I tend to buy larger than my present need so I can add stuff without having to buy yet another psu.