Attachment 154831
This is my "one" rifle a Ruger scout with synthetic stock. I've used it on deer, goats and in an IPSC match. One of the things I like about scout rifles is you can set them up for different situations. Use the irons or a red dot in the bush or chuck on a suppressor and a conventional scope if you want to take longer shots. .308 may not be the "best" but its proven, cheap and available in different weights.
I also have a .223 and a .22 both are great at what they do but if I could have only one it would be the scout paired with a shotgun for small game.