I also fully agree. I have made a 5-year old P4 machine as WHS. After 2 days of running I noticed that the space around the server was very warm. Even before making it a server, I was keeping it on 24/7 as I access it from my hotel room when I am on tours. But I never noticed it being so hot.
I changed the power settings to switch off the hard drive after 45 min. That has cooled it significantly. Anyway at home we don't access the server that much as we access at work. So turning off the hard drives is not really a problem (for me, at least).