RE: Help me choose another caliber
I'm going to go against your smaller calliber. Your .308 will cover everything from coyotes to elk.
Get yourself a good lever action bigbore like a 444 Marlin, 45-70, or 450 Marlin. Big power and really fun to shoot. These are great fun and can kill anything this planet has to offer. If you have not checked them out yet you owe it to yourself to give them a shot before you buy.
If you really want a smalley caliber then I would get a .223 or 22-250 or maybe one of the new 223 WSSM's