p4's u shud be looking at about 40-45 idle, 55-60 max, depending on ur overclock etc. Prescott core P4's run hotter than the rest too.
Athlons shud be about 35-40 idle and about 50 maxed out, lik I say tho, againdepends on core and overclock.
Ive got a P4 Prescott 2.8ghz overclocked to a stable 3.6ghz and thats 45 idle and 60 maxed out.