With my newest char i've just got a lot of .308 ammo so now I'm using the Millenia's M14, it is precise, it has a good fire rate and a good damage, perfect to blow up heads

Pretty much no matter the character build I always seen to have some kind of sniping weapon. Though interestingly, I don't really use sniper mods all too often; I either don't feel like sparing some of my already strained processing power or I find them redundant. For an energy weapons build I'll use a gauss rifle or scoped laser rifle if I can't find a gauss. Virtually any other build it'll be either the hunting rifle or sniper rifle. Even with unarmed or melee builds, there are times in the game you just need a gun, and typically an accurate one. Now I can't be certain they're actually what I use the most, sniping can be kind of boring after a while, but they're most certainly what I always have most often.

The vanilla weapons I always use are the Survivalist Rifle and Ranger Sequoia. For mods, I always use RSA. I love those weapons because they are lore-friendly and not overpowered.

Vanilla weapons- Marksman Carbine, Survivalist Rifle
Modded- M1 Carbine....nuff said haha XD

Fallout 3= assault rifle and chinese assault rifle
New vegas= weathered 10mm pistol and the entrie energy armory

FNV:
When I get the ammo for it, I would have to say the 12.7 mm smg.

With mods, I like to mix up Skirmisher, Improved Throwing and Balanced Signature Weapon to make the throwing knife more dangerous, available, craftable and retrievable.

FO3:
Just started modding it, so right now it's a toss up on the perforator and an exploited Jingwei's shock sword.

Vanilla gun: hunting rifle
modded guns: Pkm From milliena (probably butchered their name) and the ak47 I love Russian guns they're cheap and powerful.

Vanilla guns:minigun, mg, grenade launcher.
Modded: HK416, PKM, AS VAL, M40A5.
Millenia's guns are pretty neat

Vanilla: A Light Shining in Darkness, Q-35 matter modulator, oh Baby
Modded: AER 14 prototype with EVE, Murdilizer, Millenias Desert Eagle

Tough question. I suppose right now it's a mix of Millenia and Ars and Aks by Heffy.

But if we're talking Vanilla. Sweet, sweet, Survivalist Rifle all the way. In a lot of ways, it's a gun that represents the whole Fallout mindset. Rugged, wild, surivivalist, damaging. It's simple, but it gets the job done.

I forgot the name of the mod but it's a golden engraved desert eagle with a picture of a suicide queen on the handle. My favorite weapon. I installed a mod that gives bullet piercing rounds to pistols just so I can use it all the time.

A gun from AR's and Ak's. Love all of them but there is one favourite but i don't remember the name of it.

Have a good one

Battle Rifle is my favourite

One of the guns i use the most is the marksman carbine, next up would be the hunting rifle

Hmm, Probably would be the Battle Rifle from GRA
For mods tho I am really into the Four-Barrel Acid Shotgun right now.

I like rifles, shotguns and flamers... But sometimes I use snipers too because I love them.

The Gobi Camping Scout Rifle

On the mod side of things, it would be the CZ805 Bren by Millenia

I use the Catalyst AAS shotgun and Walther P-38, but my favorite vanilla weapon would be the trail carbine.

I used to use the Gobi all the time. Now i use the RHINO

In Fallout 3, the hunting rifle was my staple weapon. In New Vegas, i tend to use Millenia's M4A1