If we are talking "survival" (not against humans/zombies) and "1" really means "1" (i.e. no extra conversion kits, extra fixed, folder, camp, fighter, ect) AND I have to carry them...AND the stuff to feed it, then:

Rifle: Ruger 10/22

Pistol:Browning Buckmark

Knife:Battle Rat

If "urban" (human/zombie targets) and I know I will be able to supplement with other stuff then:

Rifle: Whatever obama wouldn't want me to have

Pistol: Glock 19

Knife: SS4


If a combination of the two scenarios then:

Rifle: Ruger 10/22

Pistol: Browning Buckmark

Knife: SS5 <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />