I had this DPMS LR-308B built for me.  I still need a riser for the rail to get the scope mounted right, but for the pics I just barely attached it for effect:)

http://filebox.vt.edu/users/sandersb/AR15/AR15-2.JPG

http://filebox.vt.edu/users/sandersb/AR15/AR15.JPG

Spent all the money on the gun... hehe.  I'd like to get something with a larger objective and more magnification, but for now it has a Bushnell Elite 3200 10x40mm scope.  It was, IMO, the best scope I could buy with the remaining funds I had to spend.  I figured its best to get a lower power good optic than a high power cheap one.

Well you should be happy....it's a nice rifle.

10x is nothing to sneeze at.  pros use 'em with great effect to 1000 yards.  

i've got a SS 10x that i got for much the same reasons you've stated.
i'm just getting into rifling, and don't have any place to try 1000 yard shots, but i've done a bit at 450, and 10x was fine.
 
i'm saving for a good quality variable.  honestly, i'm kind-of wanting a higher power, but mainly for paper punching.  

edited to say:  oh yeah, nice looking rifle.  love the set-up.  put a pic in the "dpms pics thread"  and email dpms for a free hat.  
and don't forget to post a range report.  

who did the work?

D9firearms.com did the work.  They have very fair prices on all their guns and upgrades.  Best of all.... it was all in stock and STILL made to order.  Talked w/ Darrel on the phone 5 or so times, plus a bunch of emails.  About 10 days later my rifle arrived at the FFL dealer.  No shipping charges either.... pretty awesome guy.  Best of all, he sells his own handloads (which he shoots in almost the same gun w/ 0.5moa) for around 0.75-0.80 a round.  I bought a bunch of those to go to the range with to get me started... hopefully they work well and I can start loading my own w/ the same formula.  

I seriously recommend you check his site out.  Seriously.  Actually, i'm gonna post a thread on it.  He has so many articles its not even funny... and they are very well written.  He's an electrical engineer... and if you learn one thing as an engineer its how to properly conduct test!  I'm confident ANYONE can learn something by skimming his page and the archives.

Edit: Yea, I'm comfortable with 10x for now.  I know people shoot open sights (1x mag in that case) out to 100yards in matches all the time and get groups under 1''.    I figure thats about the same as trying to shoot 10x as far w/ a 10mag scope.  Not saying its that simple, or easy, just pointing out the fact that if you can track a target at 100yards w/ no mag. and shoot 1'' groups the target will appear roughly the same at 1000yards through a 10x scope.