Chicago on the company dime?
Avec is perfect for dining alone -- either at the bar or at one of the communal dining tables. It is one of my favorite restaurants in Chicago. The food is amazing (mostly small plates) and they also offer a number of wines by the glass. Here's a link to their website: http://www.avecrestaurant.com/
Also, here's a link to some reviews and pictures of the food: http://www.lthforum.com/bb/viewtopic....
Eating at the bar at Frontera Grill is always fun - and sometimes the only way to get in. I love their Trio of Ceviches, all their special margharitas (especially the one with mescal), and, if they're still doing their menu of special dishes from Chiapas, you're in for a treat.
I also enjoy the bar at Roy's (though it's a chain, it's a high-end, consitsntly good one, and if you don't have one where you live, I recommend it). I saw Alpana Singh there once.