That link doesn't show the furniture for me, so this will be a very generic advice.
The 607 gets REALLY hot, even sitting on a top shelf in the open like I have mine. I have a 200mm fan sitting on top of it to pull air out of the top. Eventually I plan on making a hole in the shelf below it to blow air up through it...
...basically what I'd say is that you want the biggest fan you can fit. Bigger fans move more air and are quieter, and since they move so much air you can slow them down. What noise they do make is lower pitched and thus harder to hear.
If you have the space, I'd put in a 200mm fan like this: http://www.newegg.com/Product/Product.aspx?Item=N82E16835146004
If not, a 120mm fan like this: http://www.newegg.com/Product/Product.aspx?Item=N82E16835200021
...the latter comes with a speed controller so you can dial it down to a speed that you can't hear from your seat.
Below 120mm the noise-to-airflow ratio gets worse. I'd use two 120mm fans for the 607, and take note of where the most heat comes out of it (the right side, I think) and concentrate airflow there.
Wire this all up to a 12v 'wall wart', perhaps cannibalized from an old cell phone or something. Or if you don't have any of those you can get a universal adaptor. Switching it to lower voltages will also slow down the fan if you want it quieter.