whats better?

I want to know if it`s better to shut the computor off at night, or leave it on. If I leave it on will it hurt the computor. I am usually on it from 4 to 6 hours a day. I would like to leave it on or put it in stand by mode. I have a new gateway 700XL, with a 3.06. some tell me to leave it on ,others tell me to turn it off, cause it is wearing out faster. Please tell me what you think. Theonly time I would turn it off if I was gone for along time, or if there is a electrical storm. I like the convinence of just moving yhe mouse and i am ready to go. I will be waiting for your reply. wwwfluffy@new.rr.com Thank you