I will be recieving a 600w adj. power supply in a trade Link and i was wondering if it is too much than I need. These are the components that I hope to run in my pc:
3200+ venice (have already)
DFI nf4 ultra-d
BFG 6600gt (maybe a 6800gt or 7800gt) (have to 6600gt already)
OCZ PC4000 VX (not sure yet)
OCZ 600w adj. (have already)

Water Cooling set up:
Danger Den D-4
DD TDX waterblock
Black Ice dual radiator
Maze 4 gpu block

I hope to one day add peltiers to my cooling set-up after i have gained some more info on watercooling and overclocking.

How much more of an overclock will I be able to achieve with the ocz over other models that are in the sub-$100 level.

Also, are there any other components in my potential build that would bottle-neck an overclock.

Get the D5 pump from danger den instead. The power supply is sweet you will be very happy with it.

I am hoping to get a D4 for a good price. Is there much of a difference between the D4 and the D5?

Not much, they modified the impellar very slightly, and added a flow control knob to the back (not sure why you would want to lower performance???) But the performance charteristics are just about the same. Either way you will be happy.

you might consider a 6800GS. They seem to basically be coming out as the new best price/performance ratio card. It's got less pipelines than the 6800GT, however it's got a higher clocked core so it pretty much evens out to a stock GT.

Last benchmarks I checked they overclocked that 6800GS on stock cooling to some pretty nice numbers and at that point beat out my 6800GT which is overclocked to 450/1200. Stock GT is 350/1000 I believe....a 6800Ultra would be 400/1100 or 1200....the 6800GS is 425/1000 and apparently stays fairly cool, so include water cooling on that and you should be able to get some nice clocks with the GS.

The highest I got in 3dmark05 was 6100 or so with my 6800GT clocked at 450/1200...that GS which was apparently OC'd on stock cooling was hitting around 6300....which pretty much made me jealous.

As far as that RAM, that basically guarantees you a 250HTT that you'd be able to run, although I don't know much more about that RAM so I couldn't tell you how far past that you might be able to go.

I don't see any possible bottleneck though so you should be good to go.

Thanks for the replies. I will try to sell the 6600gt and go for the 6800GS. I have also decided that I am going to keep the psu.

With all the hardware you mentioned, yes 600 watts is a good idea, 500 watts would probably do it, but not much of a safety margin...it's a cheap investment now that will protect you in the long run, it wont have to work as hard to feed your hungry machine.

As your computer ages it will slowly work the power supply harder (Power requirements will creep up slightly) you won't want something right on the borderline now, because a PS output also slowly degrades over time, more so if you load them heavily
(Heavy loads equals high heat , and heat is what generally kills hardware over time)

There is a reason they have come out with 850 and 1000 watt versions recently, computers are getting very power hungry with SLI and Dual core... it only gets worse when you OC em'