I know what you mean about pre-purchasing hardware. I managed to get my HDD before the rest of my tech cos I had the money. I got a 320GB WD HDD for about $140.00AUD (not too bad at the time) and now they are about $90AUD, I could have got a 500GB for the same price. I also made the mistake with my 8800GTX, it cost me $840AUD and by the time I FINALLY!!! got my DFI mobo (huge back orders on the 680i DFI mobo's) the cards had dropped to $700AUD.
I wasn't having a go at you, I know it can be hard (and expensive) to get all the tech in one hit.
One bit of advice I have for you is this. I would remove everything from the case. Then install the PSU and hide as many cables as possible and route the ones you have to use (route under mobo if you can). Then install the mobo, CPU, water block (no tubing) and RAM, connect all the required cables and try to hide some as you go. Then install the GPU and route cables. Next do the same to the CD drives and HDD's. Finally you do the W/C loop.
I found by following this process I make the PC's I build a lot neater.











