Nothing much else to add. Get yourself a basic carbine and start from there. If you get an optics ready model, you will need sights or some type of optic, as these typically do not have either one right out of the box. Another thing to watch on optics ready models is that some do not have a way to mount a front sight straight from the box. A friend of mine bought a Bushmaster and it was configured to be an optics only model.

Windham Weaponry and Palmetto State Armory rifles get good reviews from their owners, so they may be worth taking a look at.

Handguards, stocks, rails, etc. can all be changed at a later date, but if you want the Magpul furniture, it may be cheaper to buy a rifle with it on there from factory than buying it yourself.