Meson Sabika is in a beautiful setting and has heartier and perhaps more American-friendly tapas than some of the recent openings, and at last check is open for lunch.
http://www.tapasvalencia.com/mesonsabika/index.htmlDavid's on Jefferson Hill has been impressive for dinner and had plans to open for lunch, but I don't think they're there yet. The former Masala Yangu would have been nice for you, probably not so much for the guest.
http://www.rewardsnetwork.com/details.h ... ntId=93539My other nearby thoughts would be GNR Fabulous Noodles in Lisle (plenty of Americanized dishes, casual) or
Suzette's Creperie in Wheaton.
On the more casual side, I end up at the Indo-Pak places along Roosevelt when I'm out that way (
Desi Grill, Viceroy of India). Chicks 'N Salsa in Glen Ellyn gets some nice messages on the board (Mexican fast food, probably too chainy to enjoy a quiet lunch). My folks like
Honey Cafe also in Glen Ellyn, an organic-focused "comfort cafe" receiving some buzz lately.
Final thought:
Greek Islands in Lombard. I go back and forth, but currently like this location better than the one downtown.