Supergus - I think the Mil-Dots time has come and gone. In this day and age, we have the ability to down load ballastic programs right to our phones for crying out loud.
Throw in a very cheap golf "laser range finder" and you don't need a Mil Dot clogging up the target field to get on target quickly.
I have one on my .308 because I wanted to force myself to learn the system - and having done that, I will probably get it changed out at some point because it's just not necessary anymore.
A 3 x 9 is a good choice, but that 20" heavy barrel will have you wanting to stretch your range a bit, so I would suggest just a bit more powerful if you can spring for it. I don't know about you, but my eyesight is great and I still like to aim small and miss small.
The best overall entry level ranging system I have seen is the Whore-us Vision reticle, but the damn thing is so busy to the eye, and the guy behind it is a FIRST CLASS A-HOLE, that I would never buy the damn thing! Jesus but that guy thinks he is the end all beat all in the world of firearms. I had one 20 minute conversation with him at SHOT in 2004 and I knew then and there what the definition of "ARROGANCE" was....
I am in the scope market as well at the moment and I am leaning towards a Leupold Vari X II ( or III, I can't remember ) with their Varmint Reticle. It's not as busy as a mil dot and it allows several basic corrections for longer ranges ( 300 to 600 ) without having to do a bunch of math.
There is another little trick that I am saving for the grand finale on my Mjolnir project, so I won't mention it here, but hit me up with a PM and when I get home tonight I will send you a link to a kick ass idea for a more personalized scope.