Those are pretty good temps, but are probably not as accurate as they can be. To ensure 100% cpu usage, use prime95, or a cpu-burn program. These will get your temperatures up to as high as possible.
Personally, I try to keep everything under 35C at idle, and below 55C under full load. You won't start damaging your CPU until you reach 80C or so, but if you're reaching those temps, your system is probably suffering from major instability.
I've become fond of using ATI Tool to benchmark for heat. It utilizes most of your graphic card's processing power, and close to 100% (if not 100%) of your CPU. I do this because ambient temperatures are affected by the heat produced by your video card, and it will probably cause your CPU's maximum temperature to increase by 2-3 degrees centigrade. I do this personally (in conjunction with programs like prime95 and cpu-burn) because I play games, and having your video card at peak operating temperature whilst your CPU is at peak operating temperature is a more accurate portrayal of the maximum peak operating temperatures of your components.