Brad, did you ever get those sound measurements? The DTivo (Philips DVR6000 - Series 1) isn't as loud as my Shuttle computer, but it's still much noiser than the golden silence I had before I plugged it in. And yes, I finally just plugged it in after having it for over a month.
I've ordered (and am now waiting for) 9thTee's Cachecard with Ethernet (instead of getting a plain Turbonet) and I think it would be a good idea to put a replacement fan into the unit when I open it up. I may drop in a bigger drive as well because I think my watching schedule may get back-logged.
Curious what make/model fan is being sold by Weaknees. I've seen 16dba ADDA fans (13CFM) recommended for the DTivo and selling for $8.
http://phamcomputer.safeshopper.com/43/79.htm?56
Bruno