Going to be renting at first, looking for something 2+ beds 2+ bathroom and a yard for the dog and kids
Price: as little as possible for as nice a possible place 
Up to about $1500 I guess
then move to West County, that's the best part of the metro area, you can get a nice sized apartment for way under 1500, Chesterfield is nice, the cool thing about St. Louis is that everything is fairly close and easily accesible, Chesterfield has the best schools for the kids, the Rockwood and Parkway school districts are some of the best in the United States.