There are a few options that you can consider. Now you've stated that you love the performance of the Noctua but can't stand the looks and will go so far as to but an expensive closed loop cooler.
The first option I have for you is a lot less then the Cosair cooler and that is to buy two replacement fans for those ugly brown and tan fans and by doing that you would get to choose the fans your getting.http://www.newegg.com/Product/Product.aspx?Item=N82E16835181025
You could go with a 120mm and 140mm like Noctua has and select these two.http://www.newegg.com/Product/Product.aspx?Item=N82E16835181026http://www.newegg.com/Product/Product.aspx?Item=N82E16835181028
Naturally the choices are endless as there are a ton of fans to choose from. The next optioon would be to go ahead and get the H-80 or the H-70 depending on your overclocking if you are doing that.
You can also get white fans too.