for your build, you hav several things to consider. Lets start at the top of the rifle and work our way down....
1. Optics - buy the best you can get in a magnification that is appropriate for the range(s) you hope to shoot. Generally speaking a variable in the 5x-25x range is good.
2. Action - Savage action is a solid platform to start with.
3. Barrel - for barrels you have many custom options from pre-fit barrels to custom contours done by a gunsmith. Pre-fit would be least expensive and as other have said, they generally shoot well.
4. Caliber - 300winmag is a good all around choice but if you are mainly going to be shooting varmints, give the 6.5mm cartridges a good look. The 6.5x284 will send a high BC bullet like the 140grain VLD really fast, really far, really accurately. It will also have far less recoil than the 7mag or 300mag.
5. Stock - for a longrange rig, look for a stock with a verticle grip and give real consideration to an adjustable cheekpiece. Others have mentioned some good options with the Bell and Carlson Medalist line. to see a large array of stocks and prices, check out www.stockysstocks.com
When you do upgrade your stock, have the action bedded in it.
6. trigger - Does your rifle have an accutrigger? if it does, adjust it down to 2lbs or less.
then acquire target, maintain sight picture, relax, breath, pause, squeeze...bang!