M&P Sport for $599
When the Sport came out people made fun of it's melonite barrel. Read up on it and learn about its benefits. The 1-8 twist means it can stabilize a wide range of bullet weight/length (I've shot 55, 62 and 75 gr fairly well with it). Most shooters will never need the forward assist or ejection port cover. If you do, then need to buy a different rifle.
The different rifle is PSA's offering for $699. 1-7 twist with chrome lining. Your basic M4 clone. They are build to order so it can take some time to ship. Like someone said, add the cost of FFL fee.
Good luck with your search.