So many rifles, so many choices.
You need to decide the configuration you want first.
Flattop or carry handle (A2 -vs- A3)?
16, 20, 24, 26" barrel?
plain barrel, fluted, muzzlebrake?
Standard handguard, Vmatch floating barrel, DCM floating?
If you just "want one" and will be doing plinking, CQB and stuff out to 300 yards, I like the M4 configuration best. Light, small, well balanced.
A "standard" gun would be a 20" Hbar.
I can't recommend a place in Dallas to buy. Prices vary regionally. If you wanted to order, I'd recommend talking to Gunsmoke at www.ar15.tv
and explore having them build you a Bushmaster with the 20" govt profile barrel and a 4 slot muzzlebrake. It'll look like a GI Joe issue, be lighter than the standard HBar. They just did that barrel for me and it's nice.