I'm planning a surprise (shhh!

) trip to Chicago for my BF's birthday in July. I got reservations at Alinea for the special day, but I have no idea where to eat for the other three days. I need some breakfast/lunch places and a couple of dinner spots.
I also trying to figure out what we should do while we aren't eating

. I know there are some awesome architecture tours but there are too many for me to decide on my own.
We are staying at the OMNI and I'm not planning on renting a car (do we need one?), but taking cabs is no issue for us if they are easy to get.
Also, what should we do at night???
So basically, all I've done so far is the flights and hotel and Alinea. I need help with the rest! TIA