Stag, Spikes, BCM, Core, Windham, Ruger, Sig, STI, Daniel Defense, S&W.
It's pretty hard to get a bad AR these days as long as you stay away from Chinese made AR's. My advice is to spend some time shopping around all the site sponsors and make a list of every rifle you can find within your budget then pick the one that comes with the barrel length you like best that's dressed up in the furniture closest to what you like. Barrel and trigger quality makes a difference so also keep that in mind when deciding.
I had a Stag lower a year or two ago and it had the nicest factory trigger of all my AR's so far.
Remember that furniture is cheap to replace but barrels start around $300 for a good one and then you either need the tools or you have to pay someone to install it.
Decide if you want a telescoping or fixed stock. If you like telescopic then don't worry too much of it comes with a standard 6 position plain jane as they are super easy to change but if you buy one with an A2 rifle stock then want a telescopic you need to change the buffer tube, buffer and spring.
There are many factors to consider when picking an AR but brand name is more of just a preference these days if you're sticking to a direct impingement rifle. Most rifles are very good quality and will serve the average recreational shooter well for years.
Best thing about an AR is that you can change everything.
Don't worry too much though, once you have one you'll start thinking of the next one and before you know it you'll have a couple then three. I was up to six a few months ago but am now down to four and have my AR-10 on the EE. Pretty sure I'll regret selling that beauty but I need some cash and something has to go.