OK. since you are buying the waterblock new, spend a little more and buy a Swiftech Apogee XT instead. It's a newer design and all around better performer. According to
skinnee Labs, it's about the best performing 1366 block on the market right now and it has a very good mounting system.
Motherboard block - I have no idea on that as I don't have a 1366 system and I don't use nb or mobo blocks on my 775 systems.
Pump - good choice, but a little bulky. The MCP355 with an XSPC Res top will outperform it and be more compact, but will cost over $100.
Radiator - I would go with a minimum of a Swiftech MCR320 rad and since you also want to cool mobo components with your loop I would also consider going with an XSPC RX360 rad. You can mount it externally with a
Swiftech Steel MCB-120 "RadBox" Rev.1 off the back side on your case. BTW, the Rev 1 I linked is much better than the current Rev 2 Radbox, which is made of plastic and much more flimsy and fragile than the older Rev 1 model. For fans, I would suggest some Yate Loon mediums from Petra's also as they are relatively inexpensive and work well on rads and are relatively quiet.
Tubing - PrimoFlex is some good stuff, IMO.
Tubing clamps - I've used the plastic ones and I have used automotive worm drive clamps and I much prefer the worm drive clamps for a more secure connection.
coolant - I use distilled water with a few drops of PT Nuke in them. I don't believe in aftermarket additives or dyes as I think you are asking for that crap to break down over time and cause mayhem to your loop. If you want color, buy yourself some UV reactive tubing instead of using dyes or coolant additives. Using distilled water with some PT Nuke or PHN Nuke will keep the loop nice and free from algae and other microorganisms.