Software Daily

I was thinking that it might be nice to get my husband some CAD drawing software that he can use at home, but I am not sure which one I should purchase. He is an engineer, is there some type of CAD software that is more commonly used among engineering companies? I want it to be a surprise, so I don't want to have to ask him. That way he can try to design things for fun on his own, or maybe work from home sometimes even if he has not remembered to bring his work computer home with him.