Get the shorty carbine WITHOUT the extremely loud muzzle brake and pay the extra money for the removable carry handle model. For a scope I bought a IOR m2 tactical, they run around $ 350 w/ a mount. I wouldn't buy a scope right away. Shoot it for awhile the the iron sights, then decide on a scope.

Quoted: thanks for replying.  I have a couple more q's for you.  1. what is the difference b/t carbine and steel barrels 2. what advantage does the removable handle have 3. Are their any other brands of ar15 that you would recommend over the bushmaster, and why? thanks for the education.

1-Carbine v. steel barrels-not sure what you mean
2-removable carry handle- allows you the option of mounting optics directly on the rifle, instead of on top of the carry handle, by unscrewing the carry handle and removing it from the rifle (you can still mount a flip up back up iron sight). You can mount a scope to the top of the carry handle, but you might prefer the removable carry handle as that allows the scope to be mounted lower-this makes it easier to get a good cheek weld.
3-I wouldn't recommend another carbine as being better than a Bushmaster. Bushmasters are the only AR style rifle that I have shot any significant amount, as far as I can remember. The answer that I usually see here is that the ABCs are all okay (Armalite, Bushmaster Colt). I have also heard favorable comments about Cavarms, DPMS and Rock River but either have not used these rifles, or have fired them very rarely.