id do the CPU first; it is THE most important chip of the three. the GPU does get very hot under load, so id put that 2nd. and i wouldnt even bother watercooling the NB becuase it doesnt get that hot (but you know what they say, if you're gunna go out, go all out
). i guess it depends on the blocks you are planning to use and the flowrate thru the system.