So many places to choose from, so little time! Chicago is really a great city for great dining.
Not knowing your budget, a few places that come to mind.
Tru:
http://www.trurestaurant.com/welcome.html
Pasteur (Vietnamese):
http://metromix.chicagotribune.com/d...mx-dating_heds
Pasteur is up in Uptown/Edgewater. On the pricier/fancier side. Plenty of other Vietnamese restaurants in that area too where you can grab a great bowl of Pho or Bahn Mi.
Spring:
http://metromix.chicagotribune.com/s...,7966851.venue Asian influenced and heavier on the seafood. Interesting space. Great bar. And in a good neighborhood (Bucktown/Wicker Park) to walk around and check out. Lots of other great places to choose from to eat. Also nearby is Le Bouchon which was mentioned in the prior post
http://www.lebouchonofchicago.com/
Ann Sather:
http://www.annsather.com/ Especially known for their Cinnamon Rolls. Several locations, though I like the one up on Belmont near Boystown
Also in Boystown is Yoshi's Cafe:
http://metromix.chicagotribune.com/s...,2981529.venue Interesting mix of different cuisines. Higher end food but in a great relaxed and very casual environment.
You might want to check out the Chicago forum too. Sweet Willie posts restaurant reviews all the time.