I'm glad to see that you were convinced. Believe me, not only have you chosen higher performance but possibly a cheaper solution.
The advantage to WC is that there aren't too many options like a custom built computer is. With computers, there are tons of different kinds of hardware with many different manufacturers. It's very easy to get confused.
With WC, your choices are very limited so making a good choice isn't difficult. To be honest, I think the rig I'm ordering soon would be a good fit for you (check sig).
The heatercore will outperform most radiators if not all of them. And it's only $35! Some people buy ridiculously expensive radiators like +$75, which is a fat waste of money when you can use a heatercore. Not to mention that it comes pre-modded with fittings!
The D5 pump is really the basic pump that does the trick. Whether you get the Laing D5 or the Swiftech MCP655, they are exactly the same. You could also consider the AquaXtreme 50z. The difference between the two is virtually non-existant. There are many more expensive pumps out there, but you decide what is necessary. The D5 will do what you NEED, depends on what you want.
Obviously you want the Danger Den TDX CPU block. You can get the RBX for a bit more money, but it's really all the same. Again, you will want to compromise between price and performance. If something is more expensvie for a really unnoticeable difference, why bother?
The Danger Den MAZE4 is the same story as the TDX.
Tubing can be a bit of a tough decision, even though it really shouldn't be. The Tygon 3603 tubing that I'm going to order is the best and most expensive out there ($2.75 per foot). I went to home depot and they sold 10ft of vinyl 1/2" ID for a total of $2.67. That Tygon can cost over $20 more than the generic tubing. However, the Tygon can bend much more easily and has much lower resistance. Tygon will last you much longer. It really depends on how much you value the ability to bend, and that will depend on how your case is laid out. If you have a small tight case, you will obviously want a tubing that can bend easier. You decide. Clearflex 60 is also top tubing and is slightly cheaper than the Tygon.
Some will definitely argue the quality of the parts and "this is better than that" and so on. What I suggested is basically from what I heard from others and reviews from other websites. I can't say for sure that it's the best possible solution because I don't have it yet. Give me a few weeks, and I will surely let you know.