The Chicago Reader has a good feedback based online guide - heres a link for 1/2 mile radius of Symphony Center:

http://tinyurl.com/ux9lc

I've been to the Village, Trattoria No. 10, and Elephant and Castle - Each is acceptable, non are amazing.

Petterino's is very well accustomed to dinner and show patrons from being along side Goodman Theatre.

Closer ones with good reputations include:

Park Grill - on the Michigan Avenue Side of Millennium Park, just under "The Bean", and therefore a great choice if you haven't been to MP.

Russian Tea Time - old school decadence

17West at the Berghoff is a new incarnation of a Chicago classic (same ownership as Berghoff Cafe at ORD T1)

I know little about Rhapsody except that its French dining and right behind the Symphony Center on the same block.

For a taste of Chicago, and a smaller bill try
Miller's Pub - old school photo's on the wall joint
Giordano's (Randolph) - Easy to get seating branch of Chicago-style Pizza chain.

There are also some national sit-down chain options not far away and several good choices in River North if you want to walk a little further as well (Frontera, Singha (thai), several steakhouses - but the Brazilian places are probably above your line.)