The .308 is a good cartridge, and a fine, accurate rifle can be built around it at reasonable weight and without great expense. I really like my .308, not sure how far I'd risk a shot at elk with it. 400 - 500 yards sure. Beyond that? Dunno. Farther is why I have a .300 WSM
What I do like about the .308 is that it's so easy to shoot well, easy to load, easy on barrel life and just very pleasant to get along with. I've been shooting mine for about 15 years, through several different barrels. Now and then I get the urge to re-barrel it to something else, but I always seem to come back to the .308 Win.