I love going to Wendy's and getting a jr. cheesburger and a sour cream and chive potato. Comes in around 500 or 550 calories and is really filling for me. It's my go to meal if I have to get fast food.
Also, if in a rush, and couldn't take time to eat a potato, I'll order a small fry no salt. It's a win, win really. You get fresh hot fries and they're not covered in salt, which is just added sodium.