The pic of the fan setup you saw was not loud at all. Much less loud than Delta fans, and somewhat less than the medium speed fans. However the squirrel cage fan I traded up for is a little louder, but still no where near the Delta fan levels. Plus I added a rheostat to it, a light dimmer switch (made detached with a cord) so when I am not using my system hard, I can turn it down untill it is real quiet. You'd have to listen for it.
And yes, there were postings about running duct from window ac units. I even answered a few questions concerning them posts. The small 5000 ac units will work surperb in cooling a computer, but it is quite expensive to run them, plus you gotta have them vented to the outside. OTOH if your computer would be relatively close to a window, say less than 12 foot, and you could run 4" duct from it, and you fixed a way, a bonnet, too force the ac'ed air to your computer, and still use the ac for room cooling when you're not pushing your computer, then you might have a good excuse to go that route. Unless you just happen to have the money to spare. You can get a small new 5000 btu room ac for about 125 bux.
For those who are going to ask about the ac causing sweating or condensation inside your computer. You should be fine as long as the inside humidity is below 60%(I am erring on the safe side here.). The lower the better, as well as ambient room temps. The trick is, too get as much ac air as possible into your computer system to begin with, because ac air has already had most all of the humidity removed from it! It is already dry air! Therefore you would want to keep outside/room air from mixing with it in your case, as much as possible. Sill a 50/50 mix at 60% humidity (room air) would still be very difficult to cause condensation your case, as you would only actually have about 30%-40% humidity in your case to begin with!
The ultimate ac computer setup would be having a 7500 btu or even larger room ac setup outside, next the wall your computer would be at. (Mite need 6" ducting with larger ac units.) Even an old room ac without the case cover would be excellent, and have a 4" duct pipe run into the house (maybe through the wall, and into the back of your computer. Now have the ac sheltered or in a cooler place, out of direct sunlight and run some switching controls inside, so you can control the ac from your computer desk, and you would definitely have something that could compete with and most likely outdo water cooling. (Do you a little mini-duct straight from the supply, where the ac comes into your computer, to the h/s and it would be awesome! You could pretty well cool your whole case and contents down to almost freezing! only problem is you might have to pay just a little more attention to the possibilities of condensation. )
Cheers,
Mike