Having a pump between a block and a rad.

Well, for one. I don't think you would need two pumps for that setup. What pump is in the res/pump combo?

Also. I've completed a very similar build in a 700D a few months ago. Your bottom EX140 will be a royal pain. It's going to be very difficult to find the right size fittings and you'll have to get a bunch of 90 degree fittings to make that fit, it might hurt the flow.
Edited by axiumone - 8/4/12 at 7:04pm

The ideal setup would be Pump > Radiator > Block. This would ensure your block gets the coolest possible water. Having a Pump > Block > Radiator loop means the water running through the block will have been warmed up a little by the pump, but it's not a big deal.

Your proposed setup is pretty good, although I would argue two pumps are a bit overkill and you really don't need more than a single 360mm radiator (unless every degree is critical).

If you're not in a hurry. Wait for this, it may be better.

This is inaccurate - in any water cooling loop, the temperature of the water equalizes throughout. The water is not cooler after a radiator, this is a common misconception. Perhaps for the first minute after switching your PC on, but after that, the heat will move through the entire loop and the temperature will be equal in all places. The order of reservoirs/pumps/radiators/blocks in the loop does not affect cooling capability at all.

To the OP: the only time order of parts comes into play is when filling your loop. This is MUCH easier if your pump comes immediately after your reservoir. When filling, you can put water/coolant into the res, which will move straight into the pump. If there is another part between the pump and res, you will have to fill it before the fluid reaches the pump and this can be tricky. Pump/res combos are the best option IMHO.

Edit: your proposed loop means that to fill properly, you'll have to fill the reservoir, then somehow force the coolant through almost the entire loop before it can get to the pump. This won't be impossible, but it will be extremely difficult and most likely lead to air bubbles being sent into your pump which can damage it. I would consider moving the pump to one of the hard drive cages and reversing the direction of flow. That way, the pump is after the res and it allows for easy, gravity-assisted filling. I've edited your original picture to show you what I mean, but I can't upload it here, because I'm at work and my computer is locked down with Java disabled. Find it at this link: http://farm9.staticflickr.com/8287/7722942854_37b5df44e4_z_d.jpg
Edited by Captain Lolburger - 8/5/12 at 9:43pm