id like to see you try use your computer without a keyboard and mouse...
id say its kinda important part!
gaming mouses can be as high as £50 (iv seen anyway) for a high resolution optical one! thats more than my hard drive, speakers, dvd writer were. so a really good mouse would be something to show off!
i use a labtec ultra flat wireless keyboard, and a packard bell optical wireless mouse. (windows doesnt exactly like the matching labtec mouse very much! cursor freezes continuously on startup)