In a perfect world
You can give the baby a bottle, eat a meal that didn't come out of the microwave, and chat with grown-ups all at the same time.
The barrage of unfamiliar sounds and smells can turn the calmest baby into one cranky little customer whose wiggling and fussing will make cutting your steak a challenge -- and will probably annoy the other patrons. But it is possible to have a nice meal out. Schedule it for a time when your baby will be rested and fed, go early -- 5:30 or 6 -- and bring toys. Ask for a booth and set him next to you in his car seat (or place it securely on top of a high chair). Keep in mind that if he begins to act up you'll have to hold him, so order food you can easily eat with one hand. And although you don't have to go to a place with Formica tables, you shouldn't choose the one in town with the linen tablecloths either. You might also call the restaurant to ask whether if it's a good place to bring a baby; the reservationist will be frank and you'll have a much more pleasant experience if your newborn is welcome.
Go -- just be prepared to ask for a doggie bag.