Unless you're hunting dangerous game, the caliber choices for big game will be no different than what you'd encounter in North America. Most on this forum are going to suggest any of the 284's or 30's... standard load for under 800's and magnum for longer. For LR hunting you'll get recommendations for Sierra Game Kings, Berger VLD's, Hornady SST's and Accubond LR's. Rifles will range from custom builds, Rem action with a semi-custom, and off the rack guns that you'll need "accurizing".
IMO, if you already have a rig that you're competent using, then stick with it. Obviously, if you're just wanting a new gun, then disregard my last comment.