some misconceptions to clear up
1.) Cascades are no longer available form Cathar, you must find someone hwo is willing to sell one. That is why I said $150, and $150 is a low price to sell one for, considering they are the best block on the market.
2.) Do not spend more than $30 on a heatercore or radiator. That stupid 120.3 is the best waste of money ever. Go to your auto parts store, and look at their catalog. Find one you like. Buy it.
3.) I personally do not like DangerDen, as they "borrowed" Cathar's design, for their RBX, but if you choose to go with them, so be it. The RBX does not mount well on a socket A chip, though. I'd go with the D-Tek WW there.
4.) The aquaextreme pump's reliability is yet unknown. Go Swiftech MCP600 for silence, Laing D4 for performance, Iwaki if you don't mind a 120v larger pump, but want max performance. The Iwaki is a little out of your price range if you get GPU and NB blocks, though.
5.) Seriously think about the NB block. I really, really, really feel it is a waste of money, and will hurt system performance. Many people have gotten NF7s to 250+ FSB without watercooling on the NB.
6.) you should probably mount your rad in the top of your case, and you'll need to cut the case if you do that
7.) res or t-line?