Cappy,
Guids suggestions are spot on -
If you only have one day to explore the city, you probably should spend it in wrigleyville or lincoln park.
check out these resources:
www.metromix.com
www.chicagobarproject.com
Barleycorn is a huge decent place, but it's probably better for big groups. Irish oak and Goose Island are ok for some drinks. Also, most places in wrigleyville have no cover.
Lincoln Park is a trendier type of area, but plenty of low key places as well.
I agree that rush&division area is more for touristy crowds - I'd probably skip it.
Just pick a neighborhood and barhop.
Eat at Giordanos!!!!