Good part selection you've got......cannot think of much I'd change at all.
For external rear mounting of your rad, about the most used thing is this, the Swiftech RadBox:
http://www.petrastechshop.com/swmcrre2raho.html
Works quite well and will hang your triple without a problem.
How much tubing? Dunno, but order a bit more than what you measure your proposed tubing run will consume to give extra for the inevitable "Dammit, I cut it too short." Maybe like 10ft.? Don't know how long your run of tubing will be.....but a decent starting point. But honestly, you're probably only going to use about 4-6ft in your setup; that sort of length seems to be about what most end up using.
Barbs.....you need one in and one out for each item the coolant flows through. So, your cpu block needs two, your pump needs two, rad needs two, etc. And, consequently, you need a matching number of clamps for the number of barbs you purchase.
Also, you need to think about how you're going to mount your pump to your case. Petra's has a good selection of pump mounting brackets if you feel like going that way....
http://www.petrastechshop.com/moha.html
Otherwise, looking quite good to me.
Oh, and since you're going with the XSPC res top, something else to consider. That is how to neatly fill the res, esp during the purging phase when you're purging the air from your loop and having to add more coolant frequently.
Granted, the res top does have a capped off opening that you can use to fill through, but depending upon where you mount your pump, it could be rather hard/difficult to access it neatly. The link below is an adapter for the fill port so you can put a standard barb into the res and then run a length of tubing from that to any point in your case.
I've done this with my res, which is a Swiftech MicroRes. I've got a barb installed on the top of it and then run a length of tubing from it to a fillport I've installed into the top of my case, giving me external access for filling/topping off my reservoir.
The res top adapter:
http://www.performance-pcs.com...=368&products_id=24088
Fill port:
http://www.jab-tech.com/Danger...rt-Delrin-pr-3489.html
The fill port is pretty much found everywhere, but the res top barb adapter is pretty much only found at Performance PC's.
Just something to think about......and to use it, you'd need to add a barb to your list specifically for the adapter. And make sure you consider the length of tubing in this, too.
