Either will work fine out to 400 yards but you can get a good, aerodynamic 120 gr bullet in 25 caliber that will make it a better choice out a bit farther than that, so my choice would be the 25/06 so long as we are not talking deer over 200 lbs. Bigger deer you would be better served with a 7 Mag for long range shooting.
FWIW - I have killed deer at a measured 550 yards with my 7 mag and very routinely kill them at 400-450 yards.