I'd like to build my "perfect" do-it-all and stick to it. However, I've had mishaps where having a back-up really saved my bacon.
But, if I had to just have one, this is what I'd build:
-Action: Trued Winchester M70 Stainless CRF
-Barrel: 24 or 25 inch PacNor, #3 contour, 1 in 10 twist, 5 groove, recessed crown
-Caliber: 300 Win Mag
-Stock: McMillan EDGE, Black w/1 inch Decelerator
-Bottom Metal: Williams 1 piece
-Mounts: Leupold Dual Dovetail, Matte
-Scope: Leupold VX-3 3.5-10x40