iMac is warming

Question

I've 22 inch iMac. I am using it about 1 year and just noticed that the top back of the screen is very hot as i can't put my hand about half a minute on it.

I've googled some and downloaded istat Pro. Here are the temperatures of my system:

• HDD: 56 degree celcius
• CPU: 51 deg.cel.
• GPU Diode: 69 deg.cel.
• GPU Heatsink: 67deg.cel.
• Mem Controller: 57 deg.cel.
• Optical Drive: 50 deg.cel.
• Power supply: 59 deg.cel.

Are these values normal? or something going wrong with my computer?

By the way, i am not sure if there is any relationship but, i ve just upgraded to Mac OS X Lion. is it irrelevant or?