180mm fans just dont have the pressure that something like a 120mm or 80mm fan has so it wont force the air in as hard thus it wont force it out as hard. Plus, even though i love EVGA, i have never had a card from them that was cool and quiet with the stock cooler. Plus, they require using MSI Afterburner to keep them cool so that spoils the quiet while gaming. a 660 TI will also need a good intake of fresh air if its being gamed on. Plus, as you said, its over the cpu not the gpu.
imo, its just a better and much less expensive route to go with an ATX/M-ATX format.
I have very acute hearing, even the smallest noises drive me insane! haha. i can hear the one cheap 80mm fan i have on half voltage(across the room) that cools my yamaha 5.1 receiver.
Still though, ill give you that hands down. I think i just like to obsess over the needless details!