Mattri
There are plenty of good choices out there in the $900 - 1100 range. Bushmaster, Colt, Stag, S&W, DPMS, SIG, RRA, Armalite, etc. A lot of guys have specific makes they like better then others, but frankly most all major names on the market are good, reliable guns.
Couple features I would look at include forged upper and lower, forward assist, dust cover, detachable handle with a picatinny base for ease of scope mounting, and a good trigger. If you want a true mil-spec rifle, Colts have become more widely available at good prices, heck, even the local Wal Mart now sells them here in PA. I particularly like RRA rifles, as many models are available with a good quality two stage target trigger, saving about $200 in future trigger work, an making for a good base for further uppers.
Take a look at the various manufacturers web sites, see whats out there that fits your wants and needs. When you have a couple in mind, a search on sites like Gunbroker.com will usually find a good selection. Your can order one for delivery to your local dealer, who usually charges a $20 - $40 fee for the paperwork. As with anything, stay away from the absolute cheapest rifles you can find, and dont overpay for features you dont need, like propriety designed gas piston models. My favorite all around AR is probably my Bushmaster M4 style carbine , equipped with a scope, back up holographic site, combat sling, and flashlight, as shown below.
Larry