On my Alu 2.4 MB the CPU is at 40 - 45 doing light work with WiFi on, Plugged into Magport and basically doing some word processing/Safari browsing for revision for exams
Much better than my previous BlackBook, used to get 60 degrees doing nothing!
However the only downside to this is my HD is kinda loud, not very loud, audible in a quiet room and sometimes clicks every 10mins. Might have to replace it but dont want to send in my MacBook as they really screwed up my Black one, scratched it up, hinges came back loose and keyboard corners were rough and dented. They replaced it all but it took them a lot of time and I needed a Laptop so I really cant afford to go through with that all again.
Any ideas?