As you drive through Indianapolis, don't take I-465 around - stay on I-70. You'll get a spectacular view of downtown even if you don't stop. I don't know if you are going to be coming through Indianapolis mid-day or evening so I'll give you some suggestions for all:
Deli - Shapiro's Deli on S Meridian St. - great kosher deli
Full Service - Downtown Indy has great food for all budgets. On the high end you can't go wrong with St. Elmo's Steakhouse. The shrimp cocktail is a must! The owners have also opened another restaurant called Harry & Izzy's (http://www.harryandizzys.com/) where they also serve their famous shrimp. If you are more into seafood than steak, I would recommend the Oceanaire. For good food that's a bit easier on the wallet, try Palomino for more traditional or the Rathskeller or Barcelona Tapas for more European flavors.
For a quick lunch/dinner, we like the fish and chips at the Claddagh Irish Pub. If you try it, make sure to ask for the seasoned sour cream. My husband gets the full order so he can have it for lunch the following day!
Most of the places I mentioned are not too far from Circle Centre Mall. Rathskeller is further north (near the Murat Theatre) and Shapiro's is south.
Check out http://www.indydt.com/restaurantstemp... as all of these that I have mentioned have info/links through this sit.
I still love my lovely little italian place Paradisio in Urbana, Ohio, just 15 minutes from 70 on 68 between Dayton and Columbus and they just added additional hours -- we also have Crabills Hamburgers which was has mentioned in Bon Appeit and many other magazines for their hamburgers and a bargin at $0.95, but you will need several and a good stomach, but they taste soo good