Sorry but I've got another question?

If I customize my own computer through a website, what kind of specs do I need. Such as what kind of processor, How much memory, how much hard drive, what video card and so on. Again, I will be using it for mild gaming...my husband plays things like Command and Conquer, Stronghold, Settlers and I play mystery type games such as Agatha Christie, Nancy Drew and I also download games off the internet. Thanks