Non-Bar late night hangout
The White Palace
24 hour greasy spoon/diner open since 1939
When I worked 3rd shift I ate there frequently (usually at least one milkshake a week, oh to be young and thin again! lol)
Canal & Roosevelt, right by the new Whole Foods
White Palace Grill
1159 S Canal St, Chicago, IL 60607
Depending on how late you need, there are two perfect options, right in the South Loop where you want them:
Eleven City Diner is at 11th and Wabash. Shakes and malts, pies and cakes (in addition to burgers, deli specialties, and breakfast all day). Although they're only open till 9 pm during the week, they stay open till midnight on weekends. www.elevencitydiner.com
Hackney's is at 733 S. Dearborn. No shakes AFAIK, but they have desserts and root beer floats (as well as burgers, French dip, onion ring brick, and lots more). Open till 11 pm during the week, 11:30 on weekends. www.hackneysprintersrow.net
FOUR GREAT CHOICES:
Tempo Restaurant on State street in the Goldcoast is open late late late. Great breakfast food or Greek menu as the rest is only so so.
The original Third Coast on Dearborn on Geothe (1-2 blocks north of Division) is open late, serves decent grub, and has a cool oldschool coffee house vibe. Occasional live acoustic jams.
Iguana Cafe on Halsted just north of Grand. Cool nonbar place and open late. Intesting crowd too.
Artopolis Cafe Bakery on Halsted in Greektown is great as well.