I use the swiftech Apogee gt block. Just to say swiftech and danger den blocks are optimized for high flow systems useing 1/2" i/d tubing hence a higher flow rate producing better cooling (you probably know this but just in case)
Some small water cooling kits use 1/4" tubing, Allright for your first atempt at w/cooling. One thing to mention is that the 1/2" barbs have a rubber "0" ring to make the barb water tight, There can be a problem here as your not supposed to overtighten the barb to the "0" ring. Because the tubing is so strong, When you move it around to fit onto all barbs your useing it can loosen the barbs. I would deffo recommend useing some PTF tape to get a good tight sealand of course allways check there are no leaks by powering up your PSU via the green and black wires so theres no power to your onboard components