It depends all about your gaming style. In my situation I use rifle and knife.
70% of my kills are done with rifle, so the rest 30% is for closer fighting (I use longrange rifle). And because for close range fighting I would need closerange burst pistol, which I hate because you can shoot 4 bursts before reloading and nearly never you hit with all 4 if enemy is moving, you have to be super lucky. And after reloading you are probably already dead. So if I would use pistol, I would take the verylongrange (because it has more bullets than in the moderate / longrange) and it wouldn't be as handy as needed in close fights, it isn't close range weapon at all. That's why I choose knife, it beats burst-pistol because of only 4 "shots" and verylongrange/longrange because they aren't for close fighting. There's my explanation ^^