It really depends on what you want the bullet to do. There are different theories of how a bullet should work.
Some bullets (of which the Barnes TSX is a good example) are designed to retain 100% weight, expand a wee bit, and blow a hole clean through the critter slightly larger than the caliber of the bullet. You can use very "light-for-caliber" bullets at very high velocities when using this theory.
Some bullets (such as the Nosler BT or Nosler Partition) are designed to loose a bunch of weight at impact and throw shrapnel around inside the body cavity. You need a "heavy for caliber" bullet to make this theory work well, because if your bullet looses 50% (or more) of it's weight in the first 6 inches of penetration, you need the remaining bit of bullet to have enough weight/momentum to finish punching that hole clear through to the far side of the critter.
Of the two theories - I kind of like theory 2, myself. I've shot critters with bullets that do the high weight retention+mild expansion thing, and I've shot critters with bullets that came apart on the way through and turned the critter insides to jelly. The ones with the insides turned to jelly hit the dirt a lot faster than the ones that just had holes in their lungs (but all of em died, and none of em ran far enough to be all that hard to find). So what, if under theory 2, you loose a bit of shoulder meat if you didn't get a clean broadside shot - big deal, the front shoulder meat isn't exactly great eating in the first place, and other than moose/elk sized stuff, there's very few pounds meat lost if you loose the whole darn thing.
The other thing, specific to the Nosler BT that should be considered - is impact velocity. The overwhelming majority of the guys I've talked to over the years who swear by the Nosler ballistic tips as being good stuff, do at least one of the following two things: they shoot heavy for caliber bullets at fairly modest velocities (say 2600FPS or less). On the other hand, the majority of the guys I've talked to who say the NBT is a useless explosive piece of junk, do one or both of the following: shoot light-for-caliber bullets at pretty high velocities (in excess of the 2600FPS or so mentioned above, often in excess of 3000FPS).
In conclusion - I would suggest to you that you shoot a 180 grain Nosler Ballistic Tip at about 2600FPS in your 308 Winchester (factory or handloads should come in within 100FPS of that velocity). That particular bullet at that velocity ought to work great on anything you're going to shoot with it (heck, I'd even shoot elk or moose with that load without a second thought).
YMMV.