Check out the Old Bag of Nails (ok, it's a local chain, but not a corporate one), there's about 6 locations... Really good pub food and some d*mn good fish and chips.
I also like Mary Kelley's, another pub style restaurant, located in Dublin. Good selection and reasonable prices. Very good sandwiches and the owners are extremely nice folks.
If you're into BBQ, check out Pig Iron on North High street, close to the Columbus/Worthington Border (full service), or City Barbecue (there's a few locations, counter service).
Down in German Village is Schmidt's, very good German food, and a nice buffet. Try their dark beer. Long waits on the weekend...
India Oven has great Indian, they're located downtown.
The only Pizza that I really like around here is Adriatico's, they're practically on OSU's campus.
For some GIANT burgers hit up Thurman Cafe in German village.
For breakfast check out The German Village Coffee Shop (right next to Thurman cafe), or Jack and Benny's or Nancy's (both on High St) in the Clintonville area. Good breakfast staples at cheap prices.
Hope this helped, I'll edit this and add more if I think of anything else!
edited to add: Banana Bean Cafe in the German Village/Merion Village area is a little funky joint with about 10 tables, everything's inspired by the Florida Keys... I had the shrimp and grits when I was there, it was fabulous. They even have a live feed to the Florida Keys so you can watch lucky people basking in the sun from your table in the Midwest ;)
Dan's Diner is all the way down High St below German Village- it's a really cute 50's style diner with a great selection. They make a great reuben sandwich (corned beef style, not pastrami) and killer onion rings...
Try to steer clear of any of the Chinese Buffets, I've yet to find one that was genuinely worth the money.
Barley's in the Short North has an EXCELLENT beer seletion, and some delicious and creative dishes to go with the beers.
Betty's (also in the Short North) has a nice beer/wine selection, and some great food that's a step away from your average pub grub (ie. Falafel at a bar, which was suprisingly tasty).
I definitely understand not wanting to go to yet another chain restaurant... Having worked in one for 3 years, I've sworn them off forever...