All depends on idea of firearms setup.
Lighter rifle with a standard scope my ideal caliber for trajectory using quality bullets with upper end Ballistic coefficients would go to the 270 win using 130's and the 300 win mag using 165's. Up to 600 yards those setup ups are dang hard to beat on trajectory and guess work in the field on hold overs. Any of the WSM's would work as well.
Heavy rifle with bullet compensating scopes would go to the 264 win mag and the 7mmSTW or 7mm rem mag. The 6.5 and the 7mm are near impossible to beat when using the heavier bullets with very high BC bullets. Shooting past 600yards these calibers preform like a dream. 6.5 140grain bullets/ 7mm 168 grain bullets and above.
There are some fast calibers out there but the price of the cartridges can leave you not wanting to spend a lot of time on the range. The RUM's, Lazzeroni's and Weatherby's can cost anywhere from $3 to $6 a shot. That's expensive range time. If you have the extra money no problem.