what is the best temprature for my computer

[madchester2000]

I have an AMD 2400 dual core with a giggabyte mother board fan at the back and the side sata drive and I have got a 430pw psu and 2gb ram which also blows cold air in the case there is no graphic card as it is onboard I am just starting to get to grips with all this my bios gives me an alarm if the temp gets up but i need to know the optomised temp. I am not clocking the processer

[Tekime]

CPU should be okay around 40-50c, mid-50's and up might be running pretty hot. Case temps will depend on ambient but 20-30c is common.