No real reason to add a mobo waterblock... as long as you still have some fans in your case, you will be fine. (i.e. at leaast and intake and exhaust fan)
Also... i noticed a serious flaw in your idea to 'liquid cool the video card when warranty is up' - XFX has lifetime warranty!!!!!!!!!!!
*lets say you go with a different brand that has a 2 year warranty... in 2 years it will probly be cheaper and more cost effective just to buy a new $150 video card than to go through setting up a whole new loop for your video card.
I see, I figured that removing the stock heatsink would void the cards warrenty (however long it was)... but I see your point that a lifetime warranty would never expire anyways heh (I was not aware it was lifetime).
I guess the question would change to is liquid cooling your GPU worth it (as far as voiding the cards warrenty, and the extra money spent)? If so, what would be the best priced 5870 waterblock?
And is the radiator going to be enough to cool the card as well as the i7 OC'ed to 3.6 - 4.0