Firstly do your fans sound overworked?
If you just have a couple of fans cooling the system then I would expect anything from about 35 - 45°C. But room temperature plays a part (all be it a fairly small part) on idle temps.
So I would say that when you install the OS and the temps are what they are now I wouldn't worry too much
OS: Windows 7 64-bit Case: Commander MS-I
Mother Board: GA-880GM-UD2H CPU: AMD PhenomII X4 965 3.4GHz(Stock) RAM: 16GB GPU: GeForce GTX 550 Ti