Well it also actually heats up a lot. When I am compiling a GWT application, the CPU usage shoots up and the temperature rises up. I was a bit scared to see it as high as 83C. Normal working temperatures and CPU usage are OK. Should I be worried?
80 degrees C is a normal temp for a modern CPU that is working flat out.
You don't have to worry until it gets in the 95 degrees C range. But as you have noticed, the normal "hot" range is actually pretty hot.
The case should not get much more than 40 degrees C, maybe 50.
My couple of months old Mac Book Pro's case gets much hotter than my old Lenovo Thinkpad, but its also much, much faster.
I was having the same issues with my mac heating up, turned out that one of the fans wasn't functioning properly. I realized this because one side of my mac was hotter than the other. If I remember correctly (which I am 99% sure that I do) there are 2 main fans on the macbook pro Santa Rosa model (from Summer 2007), one beneath your keyboard on the top right and one on the top left. Turned out that my left fan was blown so I just went to iFixit and bought another one. They have really easy walkthroughs on how to install mac components so I'd suggest just doing that, worse case scenario. Plus, you get to learn about how the inside of your mac looks/works when you open it up, which I'll admit, is pretty cool! Hope this helps.