Looks like it's been awhile since the board had a summary of Abilene chow, so thought I'd contribute a few ideas.
Restaurants near Abilene: have to mention Fort Griffin General Merchandise restaurant up in Albany. This is about 30 min drive from Abilene / off the interstate but it's got good traditional Texas food.
Off the I-20 freeway going through Abilene:
There's a Russell Stover candy outlet that has a Blue Bell ice cream counter. Good for a quick stop if you're driving through.
There's not much good chow right on the interstate; there's a Chili's and a few other places. Frankly it's pretty fast to run into downtown or down the loop, it takes only 10 minutes or so and you have a lot more food choices.
Best higher-end restaurant in/near Abilene:
One of the relatively newer places in town is Copper Creek on the east loop. Lunch & dinner. Really good Texas style steakhouse food -- kind of expensive (more like Dallas prices), but worth it IMO. This place has more of a big-city sophisticated vibe (for Abilene), so if you want to eat at a traditional rural Texas run-down hole-in-the-wall type place, this won't do it for you. This place has a wine list, cloth napkins, and Caesar salad on the menu. You get the picture.
A few other restaurants in / near Abilene:
Down in Buffalo Gap south of Abilene is the famous Perini's Ranch, open for dinner (but not every night -- call ahead). Personally I find their food to be OK but not stunning, but it's a interesting old house out on their ranch property -- ie out in the mesquite trees, not in town -- so it's the rural Texas ranch food experience for people who want that. Perini has cooked for the White House and does updated traditional West Texas cuisine (he has a cookbook if you're interested). Call for directions, the place can be a little tricky to find.
Cypress Street downtown is open for lunch and dinner and has pretty good food. Sandwiches, salads.
Harolds Barbeque on Walnut Street north of downtown is good, it's a total dive but the bbq is great. Lunch & dinner.
Hickory Street Cafe, also near / north of downtown. Kind of a southern style lunch place in an old house. OK but the menu is kind of limited - has lighter fare like salads (it's best known for its signature chicken salad). I haven't been there in a few years, I seem to remember they're lunch only.
Joe Allens is the famous steak place in Abilene that gets a lot of mentions online. Yes they did move from their old location (I heard it was some argument over parking), so they're in a new building a short distance away.
Lytle Land and Cattle Company is another steak place, similar to Joe Allens (no wonder since LL&C is run by Sharon, Joe Allen's ex-wife). Some people in town think this place has better food than Joe Allens; YMMV.
Not a restaurant but great local-made food: Candies by Vletas n the old railroad office near downtown. Great handmade fancy chocolates and candies.
Abilene has a number of chain restaurants (Sonic, Chili's, Olive Garden, etc.) -- here are a few worth special mention:
Abuelo's is a chain restaurant but it has good Mexican food from a huge menu, including some more unusual recipes that you don't see everyplace. In a shopping mall off South 14th just off the west loop. It's in the same strip mall as Hastings Books & Music, if you need some CDs for your drive.
There's a Texas Roadhouse, also on the west loop. Of the steak chains, this one has the best food IMO, they can be as good as the best local places. (However to be fair my sister prefers Outback Steakhouse out by the Mall off the south loop.)
Cold Stone Creamery is on the south of town, off Southwest Drive.
For caffeine addicts -- Starbucks is off the south loop, at Buffalo Gap Road -- but, there are a couple of local coffee places in downtown Abilene, if you want a place that's more local in style.
My top personal choices: if I could have just one meal in Abilene, I'd go to Harolds if I wanted bbq and to Copper Creek otherwise, with either Blue Bell ice cream or Vletas candy for dessert.