Good article by JB on this a few years back in "Handloader" or "Rifle" that I believe Bangeye referred to a few posts back, "The Perfect Velocity". As I recall JB didn't say it's the only velocity for all shooting situations but 2700fps with the right bullet will take care of most "Big Game" hunting situations.
IMO knowing the trajectory of the load you're shooting and the limits of how far you can shoot it accurately in all situations is more important than any other factor. Our military snipers have made some very long shots and kills with a 308 at around 2600fps. ymmv.
