I like to have a little more "gun" than "really needed". You never know when you might need it to go through a small tree before hitting the deer. Also, I hunt where I've shot deer out to 450 yards. The .270 Win is my perfect round, in an 8 lb rifle. The stainless Rem 700, 24" sporter barrel in a Sendero stock and 3-9x Leupold 2 works for me, but we have a ground blind with a "rest", of sorts.
We carry in about a mile, and often bring in tent blinds, folding seats, Coleman-fueled heater, and a few other items.
My walk-about rifle is a new T3 Lite in .243 Win, but it hasn't yet been blooded. I use Hornady GMX 80 grain bullets in it and that should be fine for deer out to 300 yards or more. Shot placement is more important than the difference between a .243 Win and a .270 Win.
Bottom line: What are you going to use the rifle for most? If varmints and rifle range, get a .243 Win. If 80% or so is deer hunting, get a .308.