I agree. if you are strictly limited to a budget, drop the fancy case/psu for generics or use what you have now if the psu is adequate. (you can get those later).
By the way, have you researched the mainboard power connectors and made sure the Thermaltake has all the right connections?
Alternatively, drop the ram or part of it and use something at hand until later. This is an extreme measure but 2gb is really not needed at all for the time being.
The 7800GT is a huge leap forward from the 6000 series and you'll kick yourself later if you don't get it.
You need to be careful with the heatpipe design on the northbridge cooler. On a similar board, (non Asus), I found that there was an inefficient thermal pad under the Northbridge heatsink and that the unit wasn't sitting perfectly flat on the chip.
I remedied this by removing the thermal pad and using thermal compound directly on the northbridge/heatsink joint. I also had to very carefully bend the pipe in several attempts to get a close or "near perfect" fit on the joint.
The process is a bit tricky and involves removing the entire heatsink/heatpipe/radiator assembly so it can be easily manipulated. This isn't rocket science but it does require some patience and care.
So, have a good look at it when you get the board, if there is an inefficient thermal pad, or the unit isn't seated properly and perfectly flat on the northbridge chip, consider fixing it BEFORE you install the mainboard.
Use great care in handling the board if you do this and place it on a clean folded cotton towel or sheet, on top of the antistatic wrapper if you want. You don't want to damage your new board!
You have to remember that these items are mass produced and that this design technology is new. The heatpipe design and mounting of the northbridge heatsink assembly is certainly vulnerable to assembly errors.
Remember, these heatpipe coolers are fanless and dependent on good airflow over the radiator, (ie. good case airflow).
The nForce4 northbridge chip is a real hotty and system stability may well depend on it's effective cooling.
