Use this calculator to decide for yourself how much power supply you need, as there are several factors to take into consideration when choosing a power supply, like future upgrades, capacitor aging, and how hard you want the power supply to work to deliver that power. I'd rather have WAY too much power supply, than just barely have enough...it can cause a lot of problems, especially since not all power supplies are created equal. Some measure their wattage rating at PEAK performance, but can only sustain those peaks for short periods of time. Others measure it by what they can do sustained. Pick and choose wisely.
http://www.extreme.outervision.com/psucalculatorlite.js...
As for the water cooling kit you have selected, it's a great kit. Dual D5s will have all the power you need to push water through pretty much anything you want, and the Raystorm blocks are some of the best in the business. The AX series radiators perform very well against other slim line radiators, and if you're to add GPU cooling down the road, I'd look to add another rad.
As for suggestions? Use distilled water and an additive...if you want color, use colored tubing. NOTHING cools as well as water. Nothing.
One last note....with all the upgrades coming right around the corner (800 series GPUs are releasing in October), and the new Haswell E series processors and motherboards with DDR4 support, among other things, it may be who of you to consider all those options before buying something now. It doesn't look like budget constraints are really that big a deal to you, so.....just something to consider.