Okay since you really don't have a predetermined budget, I'll list 2 options if possible for a single item. One option will be at the absoulte highest performance without money being considered and the second will be the best bang for your buck option.
Afterwards it'll be up to you whether to decide what you'll pick. Also I'll post whether the item I list is absolutely necessary to a watercooling rig so you can also to decide if you want it in your system or not.
So I'll be back in a lil bit with information and links as where to you get this stuff.
In a way it'll be my own reference as what is top of the line so if I should forget later on.
Maybe this will be a sticky.