Moosemike: Considering Mule Deer and Antelope I would go with a heavy barrel Remington 700 in 270 Winchester topped with a higher powered variable scope like a 4.5x14 Leupold.
And I would definitely use the wonderful 130 grain Nosler Ballistic Tip bullets!
I just recently killed a trophy 12 point (6x6!) Whitetailed Buck with my 270 Sendero, Leupold 6.5x20 variable and the above mentioned Nosler bullets.
Which brings me to the "difficult" part of your inquiry.
I have Hunted Blacktailed Deer (a lot!) AND Whitetailed Deer (a pretty fair amount) and those two species "normally" would be better suited with a different Rifle. The 270 caliber is wonderful for these two species but the scope and heavy, longer barrel is not normally the better choice.
In normal Whitetail Deer terrain/cover (NOT where I now Hunt them!) and for Blacktails in their normal terrain/cover I think I would opt for the 308 Winchester caliber with a top quality 165 grain bullet (I use the Nosler Partitions).
I have a nifty old Winchester Model 88 (lever action) with a Leupold 3x9 compact variable scope on it that I have used on these Deer in typical thicker cover and their more rolling broken terrain.
Sorry I just could NOT stretch my answer DOWN to just ONE Rifle.
Hold into the wind
VarmintGuy
