outside of that, young kids aren't horribly expensive(as long as you have good medical insurance). our 1 year old basically eats the same food we do, we don't spend a ton of money on different stuff for him. About the only expense is diapers and wipes (which is maybe $100 a month, tops)
I would list clothing as an expense, but you'll get so many clothes from relatives as gifts, and hand-me-downs from friends that you probably won't need to buy a ton of stuff, as long as your wife isn't the type of woman that needs her kid to wear brand new stuff from Baby Gap constantly. As of our baby shower. we had a whole closet full of clothes, we were basically set from 0-2 years before the kid was even born.