Smith and wesson mp 15...dats what I have and like it very much. colt is another good one....

Rock river arms makes a hell of a gun...my dad has an entry tactical with an eotech, flashlight, and something else...badass gun. Shot 1.5" groups at 100ft freehand out of the box. Nice gun, and I highly recommend rockriver arms

What are you going to use it for?

Also how much do you want to spend?

AR-15
 

Evis102 is absolutely correct. Not to be a smartass, but do you walk in to a dealer and say I want an automobile. What are his first questions? What's your budget, for what do you want to use it, accessories, etc.? All this questions will determine stock, forearm, trigger, sights, etc.

LPfishnTIM - AR15 with 5.56mm specs will shoot .223, not vice versa.

Since you appear to be a novice I would take LPfishnTIM on his generous offer, but have him show you how to assemble. That is a good way to know your weapon. Please, don't put a $29 red-dot or $39 scope and expect to have a target-grade rifle. And you don't need to buy a Swarowski scope but buy decent equipment or wait until you can.

thats right thanks for clarifing, also you can buy a vise block for assembly and a few tools and look up how to assemble the lower on youtube I have a friend building them right now he learned with youtube and a assembly manuel. you can look everything up on brownells. and as far as the cheap red dots they suck, relflex sight are good, I like the C-more, eotech, and trijicon. but they cost $$$. I don't know much about scopes but a 3x magnifier with a reflex sight is a sweet set up, especially on an ar.

primary arms red dot, vortex, bushnell, burris

eotech trijicon are frickin outrageous...

ncstar poo

eotech are out rageously expensive, but if the glass ever breaks and there is half the glass left it will somehow, supposively still reflect an accurate sight? I liked the c-more and bought one because it had the rear sight built on and I didn't have to buy a back up rear sight, which is recommended just incase the battery or reflex breaks or somehow loses accuracy.