Looks or functionality

[hotcakes 348]

You can do both. I call this the blue U.N outfit.

 

U.N Helmet

Press Vest

Rider's Jacket

Blue Cargos or similar 

Blue Mtn. Backpack

 

Just be careful of getting shot in the legs. 

[kakysas666 191]

Doesn't matter how you look, if you appear in a wrong place at a wrong time, you will be shot at. Currently I go full military gear (except backpack, which is totally unnecessary).

[pillock 850]

As the game stands, there's no real point in maxing out your inventory-slot potential. You can survive very easily with 6 slots in your trousers and 4 in your coat, using civilian clothes alone. You don't need a tac-vest, or even a backpack, really.

 

Side arm, ammo, binoculars, can-opener, rags is all you need to carry. Food and drink can be found abundantly and consumed on the spot. The addition of hunting will require more equipment to be carried, but until they adjust loot balance you won't need to even do that if you're just looking to survive and defend yourself - it's just an amusing side-track.

 

I prefer to move around without visible weapons, because I find it lends itself better to having friendly interactions - and if you don't even have a back-pack, people assume you're unarmed (though if you're very far in land, people get suspicious as to why you haven't found a backpack yet!). So, for me, fewer slots and civilian clothes is functionality.