For me.
A large rifle like AMR, some .45 handgun, 12g semi-auto shotgun and a lot of grenades.

For chems, 100+ stimpacks, Rad-X, and Radaway and some weapons repair kit.

And I can wear any medium armor that I can find.

I alternate my equipment frequently, but I always bring my Anti material rifle with a decent amount of ammo. Stimpacks, lots and lots of stimpacks. Med-x and psycho, I always try to bring at least three of each and water and food since I play hardcore.

Main Weapon
Secondary Weapon
Grenade
Ammo
Food
Water
Weapon Repair Kit
Stimpack

Currently trying a new gun kit: a Glock 17 and a VSS Vintorez. The Glock doesn't have as much kick as the .45 for obvious reasons, but it still gets the job done. The VSS Vintorez makes up for it with AP rounds. I like it so far.

be4 the comments that this is overpowered keep in mind that im talking about a seasoned survivor with a lot of experience and skill

elite riot gear (for obvius reasons)
a 44 magnum revolver or a 5.56 mm pistol (for secondary)
When it comes to main weapons i ma bit picky and choose between a lever action carbine (most commonly brush gun or a trail carbine ) a high powered rifle like the 50 cal sniper and laz rifles but mostly i go ranger style and go for brush guns and other lever action rifles

some RADAWAY of course plus 45 to 70 stimpacks

water and food (i play hardcore mode 60 percent of the time )

i hate grenades mostly but against robots the pulse grenades work mirracles so maybe 5 to 8 grenades or mines ( mostly mines i lay them of then pull an enemy towards them )

and of course ammo a knife or a machete plus some extra spare parts and repair kits (mostly 10-15 rep kits and 2-3 rifles for repairs)

oh but u need to trade with something 2 right?

maybe 5 -10 100 ncr dolars some legion coin and 25 to 30k caps

Hmmm I would probably bring the New Vegas cheat terminal You never know when that might come in handy!

A G.E.C.K. and some gumdrops, all ya need!

For weapons I'll bring a Glock 20, and a M4 with red dot, armor would be military armor with some medical supplies, and finally The Wasteland Survival Guide.

I bring Cpt.Rexs Commander Thorn armor with the DC-15b and 100000 super stimpaks.
And Desmond my companion friend of course for that little bit of support

I use light semi-auto pistols and shotguns while wearing light or medium armor.

Weapons: Ak-12, Kar 98 Fenrir, and hk usp.
Armor: Kerberos Panzer Police armor w/backpack and Gophers thermal nightvision
Medical supplies: Slasher x 50 = fun. Vodka x 25 = what
I am ridiculously overpowered even on very hard with realistic damage. I only play hardcore if I'm trying to be serious and dedicated, which I don't really have the patience for rn.

For Vanilla Fallout I go with a WW2 Loadout makesme feel original and rugged. Bedroll Kit is handy
.45 Auto Pistol for survival
.45 Auto SMG
Automatic Rifle
Battle Rifle
9mm Sub Machine Gun
Combat Knife
Roughin It Bedroll Kit
Desert Ranger Combat Armor

Weapons: anti material rifle to kill death claws and other armored creatures flamer to burn multiple targets. assault rifle for close range targets. .45 pistol when i'm out of rifle ammo i use the quick draw to pull out .45 pistol now for armor: breathing mask to breath under water. remnants power armor to deal with tough enemies combat armor reinforced 2 to take light hits from enemies. medical kit: 10 stimpack 4 super stimpack 5 doctor bags 4 weapon repair kits 10 purified water and 4 steaks

300 rounds 5.56mm
100 rounds 9mm or .45

10.5" M-4 with Glock 18
or
.308 AR and 1911
3 frag grenades

for role-play reasons I only carry clean water x8
food: iguana sticks, canned beans, and CRAM
morale: x2 bottles of whiskey and x2 scotch

6 rad-x, 4 rad-aways
20 stims and 3 doctor's bag
NVGs
Soap's MW3 Africa or MW2 cold weather setup
MW3 backpack

5 jets, a bottle of vodka, and a shot glass yep that's right the ultimate survival kit.

-Some kind of sniper-rifle, depending on situation
-A pistol, usually the "modern LeMat revolver" from Firefly or a silenced pistol
-A melee weapon, anything goes really
-Sometimes if taking on a large number of enemies I also bring along a shotgun, laser weapon or a SMG, usually the KS-23

For supplies I have 5-10 bottles of Purified Water, Brahmin steaks to eat and to grow up my Deathclaw (You get loads of them from doing the quest in Novac) and I take any food I come across.

I don't like heavy armor, I usually use the Bounty Hunter Duster or an improved Merc Adventurer Outfit and anything similar to that from mods. On higher levels I don't need to use armor at all, my perks have me covered and I'm sneaky, so I don't need to take too many hits from afar, and I have a high melee skill and the Super Slam perk to cover me in close quarters.

I like to simulate that what I would take with me in real life.
For weapons I usually start with a old ww2 SWT 40 (wich I have in real life as well,from my grandfather) and in the end I have AKS74U because it would be very plausible to find one here.Sometimes I use a G3 as well because its just awsome,firepower+badass desing
For sidearms:
They change from time to time,but I don't have more then 2 with me at a time.I can remember I sticked with the MP-443 and the MP412 Rex for a long time,but I am using Master_Shifus modified version of the Colt 1911 and lots of other sidearms to get some variety.A knife/machete with binoculars is also a must have.

For supplies:
3-5 Bottles of water and up to 6 pieces of diffrent can food from this mod here.Oh and some smokes and alcohol,for the fun of course.No drugs and stuff like that (I renamed medX to morphine so it makes sens to carry up to 2 of them) for me,I don't prefer taking any kind of drugs with me,same thing for empty syringes.I mean wouldn't take them with me in real life so I wont do this in Fallout as well.

For clothing I picked some wastelandish looking armors from Dragbody and integrated them into the leveled list+Spice of life and some other wasteland armor mods so no one looks the same anymore.I am wearing something light,not a fan of heavy power armor.The backpack is always a medium one.
For ammo I have always up to 500 rounds with me,I guess more would not fit in the backpack.

Well , Lemme think ... That's a tough one ...
For Main Weapon I would use M24E1 or HK416C from Legacy of Vault - Master Shifu's mod .
My secondary weapon is Colt 1911 (RSA) , or P226 from Public pack of Shifu's .
Some dynamites are working too .
3 purified water bottles , 15 stimpacks , 100 .308 ammo , 500 5,56 ammo , 3 doctor bags , some squirels and last , but not least - some magazines , 2 of each type .
Armor - Merc survivalist(?) suit M from BOE and sometimes Blue tiger assasin suit .

Main Weapon - G36C
Side arm - Glock 18
Ammo - Plenty
Armor- basic military gear, something like Voodoo's Armor from Medal of Honor Warfighter
Food/Chem - 5 purified water, 3 pork and beans, 10 stimpacks, 2 doctors bag's

I would try to have take something that would be useful for mos stiuations, I would bring:
A reliable Assault Rifle or Sniper Rifle, proberly an ACR or VSS Vintorez, a silenced pistol, and loads of ammo and special ammo of course (Armor piercing, Hollow Point, etc.)  
A pocket All Purpose Multi-Tool, also plenty of Stimpacks, Rad-x and RadAway
Of course food and purified water too.  
As for armor its not really an issue since im gonna be tring to NOT get shot in general anyways but i would proberly go with my favorite armor set, Soap's MW3 Africa suit