If I had to pick one, either the M14 or FN-FAL.
If I had to use one of what I have, for a SHTF scenario or something, it'd be the Garand hands down. I'm all stocked up on enbloc clips and ready to go.
I'd hole up at my brother's place with his AR-15 and supply everyone around me with 8mm mausers (k98 and m48's) and Mosins. Plenty of ammo for all of them.
I hope, and pray, it never comes to that, and I know it probably never will, but, it's pretty cheap insurance just in case.
Very interesting subject. I have no experience with the m14 or FN-FAL, but know how effective they are. I'm not to keen on the AR-15's and didn't really like the M16, but I just know I'd enjoy an M14