I agree. Yesterday when I was writing my earlier post I touched top of my iMac and it was boiling hot but when I looked from iStat my highest temperature was 53C and it was my hard drive, CPU was ~45C. It feels hot but it it really isn't. Aluminum is metal so I think it heats up too
there are billions of threads on this but anyway i cant stop myself

........i really think its case by case
for normal everyday using the imac of course can deal with its heat...hellhammer is right of course the case is built to give out heat so just feeling the case doesnt tell you what is happening if you really want to know use istat or something like that....
why would you use smcfancontrol then if the imac is fine??....well i think three possible things
first if you want your imac to last a longer time than usual most people replace 2-4 years....if you want especially your hard drive to last more in the 4-6 year range then its not paranoid to consider internal hd temps
second if you use your imac for stuff thats not email and youtube ie 24/7 rendering or other heavy work for long times....this will keep heats high for long periods and again internal hd lifespan will be affected
third if you use your imac for windows for stuff thats not email and youtube.... fan control under bootcamped windows is not great and you can get a lot of heat from heavy gaming or other heavy software.....again for regular now-and-again use if you upgrade your machine every few years its probably no thing.....
sooooo.... i think a lot of people touch their case and think they could fry and egg and get really scared about the imac melting..... thats normal imac operation
but there are some prosumer type of uses for an imac which afterall is pretty powerful now where apples default fan/temp management might not be so good and in that case i think its sensible to use istat and smcfancontrol to monitor things
my 2c

