I currently have two .308s, and used to have a third. I own a Ruger Gunsite Scout, and bought a Howa Superlite, both with barrels just over 16 inches. I had a 24" precision .308 but I sold it and built a 6.5 creedmoor for longer range, and less mobile shooting. Those long thick barrels get heavy.
To me, the .308 is perfect for a shorter barrel, like 16". It gets enough velocity in multiple scenarios. With a heavy bullet even 2450fps will drop a moose at close range. If you want to hunt smaller game like deer at further distances, the 125 grain Nosler Ballistic Tip comes screaming out at 2900fps and has a "point and shoot" (i.e. less than 6" of drop) point blank range of just about 300m.
So my advice: Get a 16" or 18" barrel. Any longer than that, and to me you might as well get a different cartridge, the whole advantage of the .308 is that it performs well in short-ish barrels.