Though most restaurants in the Raleigh-Durham area are closed on Christmas, some, thankfully, will have their doors open on December 25. A few fine restaurants, including Neo-China (offering a full bar in addition to dine-in and carry-out meals at their locations in Raleigh, Durham and Cary), Raleigh's Irregardless Café, and Herons Restaurant at Cary's Umstead Hotel are open on Christmas Day. Reservations are strongly recommended, though the restaurants may be willing to make you a carry-out meal if they can't seat you.
Casual dining options on Christmas Day are often limited to Chinese restaurants, which are usually open on the holiday. Some Raleigh-Durham TGI Friday's locations will also be open on Christmas Day, though they may only be open for dinner. For instance, the TGI Fridays in Apex's Beaver Creek Shopping Center is opening for dinner at 6:00 p.m. on Christmas Day.
Unfortunately, most other restaurants, including pizza and fast food places, close early (often between 6:00-8:00 p.m.) on Christmas Eve and are closed on Christmas Day. For instance, my local Papa John's and even my local McDonald's are both closed on Christmas Day.
So, no matter what your Christmas dining plans are, it seems wise to have some sort of back up plan for Christmas Day meals at home, even if that simply means making sure to have plenty of cold pizza in the house!