Just ran across this thread:
Is there a PERFECT deer rifle?   Is there a PERFECT  rifle or caliber for hunting Alaska?
Is there a PERFECT rifle or caliber for deer in Texas?   What if I cross the  border into Mexico?   Does the rifle/caliber perfect-ness lose something?
There is LOTS of PERFECTION,  rather a 7mm or a 270,  a 308  or a 300 mag (of various varieties).    Choose what works FOR YOU,  take the PH advice on caliber, etc,    
From my limited hunting, any 270/7mm/308 caliber  for  plains game and a 375 or 416 and you're hunting the WORLD,    add a 12 gauge, a 22 LR  and a 223/22-250  then there's no NEED to buy other rifles.
the search for the PERFECT rifle/caliber/cartridge/scope, etc  is marketing,  the  businesses getting us to by tools and toys instead of tickets and services (outfitters, Professional Hunters,  taxidermy, etc...)