I saw a Studio Hybrid the other day at Costco, of all places. I stuck my ear to the fan on back, and could barely hear it. Of course, that was an idle machine.

I did a price comparison between a Mac mini and an equivalently-equipped Dell Studio Hybrid. The Dell came in about $150 cheaper, which is certainly a non-trivial difference. Of course, if you add Blu-ray and all the other options, you can make the Dell cost much more.