Thanks for the replies guys.
In the case of some of I7 user i see why you would go cpu 1st,but in my case my x3 740 taps out 55c on load on a bad heat wave days and 5770 78-82 c on Witcher 2.I just trying to compare configuration ,if i go gpu loop 1st it just seem to be more shorter tubing streamline set up.
Second, jca, your temps are not the same as Intel processor temps. AMD processors max out at 62c, Intel processors at ~100c, and are measured in different ways and "safe/comfortable levels" with AMD processors are much lower than those of Intel.
Thirdly, if you check out my build link in my signature, you'll see my loop, which consists of two overclocked 6950s in the loop before my CPU. With that, on 24/7 folding, I see no higher than 63c on my processor, well within the "comfort zone" of Intel CPUs (room temp at about 27-31c).
I would go for the more streamlined setup over loop order (barring the pump/res business). You don't benefit from more hose, since you've got a reservoir, and the extra length can only complicate things. Shorter and simpler are better.
While common sense dictates that you would want to have each part as cool as possible by having a radiator between them or what have you, the reality is that it really doesn't make much of a difference (negligible/rounding error/standard deviation difference). It's a hard thought for people to absorb, as you can see.