Target turrets!!!
If you are planning on shooting beyond 300 yards, at unknown ranges, I would recommend the mil dot reticle, it is used as a rangefinding device and for holdover help(check the leupold or SWFA sites to see how it works); if you are shooting only at known ranges, it's not worth it. The 30mm tubes will get you more adjustment space to shoot at very long ranges (beyond 500 yards), if you are not going to shoot at these ranges they won't add anything. The larger objectives (50mm and up) will get you a bit more light, but that's only useful if you'll be hunting at dawn or dusk. The side parallax adjustment (same fuction as an AO) is convenient if you are a "tactical" shooter and don't want to move your hand to the objective, but it is of no advantage to the target shooter.
Much more important than all of the above for the target shooter, get a good quality scope with target turrets, to be able to quickly change the scope settings at the different ranges.
On scope magnification, if you want to hunt with the rifle you'll need a lower setting of about 4X (3X even better), and for target shooting you'll need at least 10X (and 20X is better). The leupold VariX II 6-18X RRider suggested it's a good option, not very expensive.
On mounts and rings, I'll pick a good quality cross slot system (weaver) or a dual dovetail. If you want to go the extra mile, lap the rings or use the burris rings with self-aligning inserts. I don't think you'll need the very expensive badger or leupold MkIV rings, and equally expensive super rugged "tactical" mounts for target shooting or casual hunting. Don't worry about the sloped bases if you are not going to shoot at very long ranges.
If you are only going to shoot at the range you could just buy an inexpensive redfield base and rings, properly adjusted they will hold very well.