I suggest you see the LCS guide in the modding section.
The best block period is the Swiftech Apogee XT.
Right below it is the EK supreme HF. The difference between the two is about a degree, but the price is $10-15 less for the EK. This is the one I recommend.
What about the rest of your Loop? For a rad, I suggest a Black Ice GTX series with yate loons, or better yet, panaflos. If you do the yate loons, get twice as many as you need and do a push/pull.
The pump I suggest you look at is the Swiftech MCP-655-B. This is basically the best value pump for your loop.
Reservoir is up to you, but XSPC passive reservoirs are the only ones that decrease your temps significantly.
Get primochill primoflex tubing. 3/8 or 1/2 inch, its up to you. 1/2 holds more water so it cools better, but it costs more for enough liquid.