I agree with what most of the others have said. A .308 is WAY more firepower than you need for home defense. Also, I'd be less worried about the noise than the penetration. Depending on the type of home and neighborhood you live in, not only could it shoot through several walls, it could potentially go straight into your neighbor's home!!!!! Plus you have to have a plan. I have a 556 and a .308 (being built) but also have a 12 gauge shotgun with a light and loaded bandelaro, a .40 cal Glock with crimson trace and IWB holster and a .45 cal Glock with light/laser also in an IWB holster, all under the edge of my bed (near my head) in their holsters (all loaded with HD ammo). I also have IWB magazine holsters for both of the Glocks. I have several other handguns but this is my home defense set up. If anyone ever broke in, I'd lock my bedroom door, grab the 12 gauge and rack it...if they hear that they may just take off
. If they come after you, at least you're ready for them. Then I'd put the .45 Glock and extra mag, at my side. Then the .40 Glock and extra mag goes in my back (DO NO FORGET TO LOCK AND LOAD YOUR PISTOLS). Then call 911! Remember...when seconds count, the police are just minutes away
!!!! BTW, I mean NO DISRESPECT towards LEOs!!!! It was just a joke I heard and thought it was funny and true (not they're fault though...they CAN'T be anywhere in seconds!). If you have children or other family in the house, you'll have to get to them (otherwise just stay in your bedroom). Try to get to your family, then just stay there rather than trying to get everyone back to your bedroom. You should have locks on ALL your bedroom doors. Put everyone in the closet, then get behind the bed or move a piece of heavy furniture around for cover. If they break through the door, blast away...they asked for it!!!
If you're just trying to justify getting a .308, tell your wife that there may be black bears where you plan to hunt and a 556 just won't take them down.