I've got my heart dead set on the Desert Tech MDR once it comes out. .308/5.56 compatibility. Semi-auto, Bullpup so it's compact, lightweight, high cap mags, and can be suppressed (.308 suppressor can be used on the 5.56 if you have an adapter). I'd run it in .308 until I ran out of bullets, then I'd barter or confiscate someone's 5.56 ammo. Top it with a Vortex Gen II 1-6x and some flip up irons.
That's if it was just me, but I expect most of us will be running in a group. Someone should have a long range rifle that hits hard. A bulk of the group should have high cap semi-auto like ARs and the women folk can carry 10/22s. Got all of your bases covered. I'd suggest you choose a handgun that everyone can agree on and everyone carry the same handgun and caliber so you can swap mags quick if needed and only have to carry one caliber of pistol ammo that everyone can share. My group is running .308, 5.56, and .45 (Springfield XDM). All of our .308s are set up to run AICS mags in Manners Stocks and we've developed a handload that works the best in all of our rifles so we don't have to worry about whose ammo we're running. AR mag swaps are easy as are the 13 round mags for our XD's. All of our ARs have .22 conversion kits if that's all we end having. Semi-auto guys have capabilities to carry 6 30 round mags on a thigh rig or HSGI belt system and we can disperse ammo/food/water amongst the group. Two people carry components for shelter (Seek Outside Tipis with titanium stoves). Everyone has basic sheltering provisions/food/water in their packs in case we lose gear and/or the people carrying that gear. We never plan to travel all together but will travel in two or three groups with runners in between and radio comms to keep in touch when on the move. We won't camp together either.
I know some people are prepping for the long haul with the 10/22s and I get it, but I think it does you no good to plan to live 2-3 years out of your backpack and skimp on your rifle to do so. The US will become the wild west. People who normally would not, will shoot you in a heart beat. I think the biggest threat to a person's survival in a SHTF situation is lack of water and desperate people. I would never want to get into a gun fight with only a 10/22. And keep in mind that there are 300+ million guns in this country and upwards of a trillion rounds of ammo (or so I've heard). The first year will see a large portion of people die off or get moved to government run camps. You should have no problem finding a gun or ammo at that point. The last thing you want to do in a survival situation is have to shoot a gun, but when you do you want it to count. Don't skimp on your rifle so you can last a year...you have to make it past week one first.
Your 10/22 might have to go up against this guy