30-06 and 308 are both great rounds. My first choice would be 308 for 3 reasons:
1. Ammunition availability and since this is a military round, you can usually find supplies of once fired brass should your friend decide to start reloading.Take a hard look at the Savage rifles. I don't have one (mine are Rem 700s) but my shooting buddy has two of the Savages and they are amazingly accurate rifles. The Accu-Trigger is no where near as good as the after market triggers I have in my rifles, but is much nicer than most factory rifles I've seen and is a vast improvement over what Savage had to offer in the past.
2. Short action rifles.
3. Looking at reloading data, very little performance difference from an 06. The 06 gains a little more advantage with the heaviest bullets (200 & 220 grain), but unless your friend is going to routinely hunt Moose, the 308 still stays on par with the 06 with the more usual weights (150 - 180 grain).
Should your friend have any interest in handloading, I would make one other caliber suggestion. Take a look at the 300 Win.Mag. I have one and with handloads, it can be loaded to 308 / 30-06 levels to make a nice shooting rifle but has the ability to go to the full house magnum loads for any game animal in North America. However, I would not suggest it as a choice unless he was going to handload as full loads can be punishing and are way too much for any type of deer.
In any case, I would suggest staying with the 30 calibers because of bullet selection. 30 cal ammo can be found ranging from 110 grain varmint loads up to 220 grain big game loads. Few calibers offer the versatility of the 30s.