Trajectory 7mm08 and .308
http://i812.photobucket.com/albums/z...blecompare.jpg
These are for Nosler accubond - same bullet design - taking representative middle of the road loads from the Nosler site Load Data who I assume won't favour one cartridge over another. You can go there to compare kinetic energy and wind drift if you like. Also consider recoil if you want a light rifle.
7-08 has infinitesimally better performance for NZ hunting between 200 - 400m so why not take advantage of it.
308 is vastly more widely used internationally.
Many calibers significantly outperform both but mostly with longer action length or more recoil.