Humm, NH-C14 in the LC17 HTPC case is going to look like a good fit... Although I found
someone with NH-C12P in LC17.I don't think these large top-down coolers, including the grand cross, are going to work in this case as there isn't enough room above the fan for it to breath, unless you want to cut a hole in the lid...
Unless you're overclocking I really don't think anything more than a good 92mm fan tower is needed. The NH-U9B would no doubt serve fine but it's $60 vs the Hyper TX3 at $18 and the Noctua's don't come with PWM fans, which most modern motherboards need to control the fan speed. Granted you may find that the Noctua can be run at a low speed on the included resistors that's both quiet enough and cooling enough for full load. To me controlled fan speed seems a better solution...
[said the nutcase that bought a very expensive NH-C14 and then a pair of 140mm PWM fans and PWM splitter to go with...]Seb