I know it's hard to spend the money,after spending so much on a fine rifle, but good glass is worth the price.After about the $400 mark though,you are paying a lot more $$$ for small increases.All the major brands,Nikon,Leupold,Zeiss have very nice scopes in the $400 range.
The 3-9X40 Zeiss Conquest is a great bargin,and can still be found under $400.The new Leupold VX2, not to be confused with the Leupold VXII, is also a scope that performs greater than it's price point and may be slightly better in price VS performance than the Conquest.
Even bargin basement scopes perform well under ideal conditions (inside the store.) With the better scopes,you are paying for better tracking and better performance in difficult lighting situations like,near dark,into the sun,and sun directly behind you.You also should get better reliability,it that your scope doesn't suddenly,without reason,loose it's zero.
Good luck,lots of good choices these days.I am partial to Zeiss and Leupold simply because they have had the best warranty track record in the business.Do not be afraid to buy used Zeiss or Leupold.I personally think you would be best served to get to a shop ,try several scopes on the mount of your choice,and choose based on the ability to properly mount it to fit you,and the way it feels and balances on your rifle.
Some scopes may make your rifle feel top heavy,so that it wants to roll over in your hands.Some may need more or even less eye relief,to get a perfect sight picture when you mount the rifle fast.I feel a well balanced rifle,that I can mount fast is better for a hunting rifle,at least the way I hunt.If you are mostly shooting from a rested position,it won't matter as much.