Power Food Center
This is the food court of Central Power Center shopping mall, and it does a really good job at it. There are about a dozen separate counters for different kinds of food, including a Japanese, a Thai and a European food counter and a beverages counter. It works with a coupon system, so first buy coupons at the booth. Then you can spend these at any of the counters surrounding the central seating area. Recommended for those on a budget.
Sinthorn Steak House
This steak restaurant is touted as the largest halal restaurant in Thailand. Obviously they serve Arabian steaks, but also American steaks, European steaks, Italian food, Thai food and from 16:00 onwards Korean-style meat buffet.
If you're looking for a quick snack, nearly all the sois of lower Ramkhamhaeng have carts serving simple street food for 50 baht or less. Aimed at the locals, prices at these street markets are remarkably cheaper than in common tourist spots. All three The Mall shopping centres have a big selection of chain restaurants in all shapes and sizes.