My favorite armor in the franchise would have to be the normal leather armor from FO3/NV. It's simple yet effective, and it was clearly inspired by Mad Max (Which I am a huge fan of). Such a cool design for an early game armor.

Think I am going to have to go with the NCR Veteran Ranger armor and helmet, they just go so well together and are just pretty bad-ass in general.

As for modded armors, I'm going with Cpt. Rex's Mandalorian armors. They are so well detailed and accurate and are a reason for my Mandalorian mercenary play-through of New Vegas. Plus, it gives a nice touch if you have some star wars blasters installed. Fits with it perfectly.

@Drinqx I do love cpt Rex's Mandalorian armors I use the red deathwatch armor myself, or Pre vizsla's

Really like the T51-B suit from the Anchorage DLC in 3... looks old yet menacing

For me the Lonesome Road Elite Riot Gear in NV and the helfire Power Armor in FO3.

there's a mod on nexus I really like right now, adds an armored version. of every jumpsuit in new vegas, even some of the legacy content jumpsuits

I would say the NCR ranger armour. It just looks so cool.

Definitely the merc adventurer outfit. it's just so awesome for me.

@Torsorapistgirl that is a good one o agree I use it before I find my favorite armors

@Kaiser Atlas

Yeah, that one was the one i used before i know it was possible to mod FO3 and NV. Now  i always use the retextured Jill BSSA outfit. It's my favorite.

I've recently really enjoyed the reinforced leather armor, something about it

Vault 13 jumpsuit hands down. Has been in every (actual) fallout game and It's such a staple that I can't help but wear it almost every playthough in NV.

Stealth Suit Mk. II, Elite Riot Armor (Especially with Project Nevada)

Desert Ranger, advanced and Elite armors shame the trench jacket was not animated

a lotta fans of the elite riot armor, it is great though
i recently started using the ''Reinforced Chinese Stealth armor'' mod with the black and blue retex and woooooooo it's nice stuff

[Vanilla] I would have to say the Security Armor from the Dead Money DLC. When I first came across it I was ecstatic and I refused to take it off even after I left the Sierra Madre.

[Modded] I would defiantly say the Rocker Ranger outfit by Cruz011. I know it only recently came out, but it's perfect and really captures the look of the Nevada Wasteland! I always feel like a proper badass when it comes to that armor!

Ah, narrowing down favorites. Always fun. In terms of Vanilla and the respective DLCs for New Vegas.

Vanilla: Merc Cruiser Outfit (I remember when I played FNV for the first time, seeing Barton Thorn wearing it as one of his numerous random outfits in my first playthrough. An instant favorite from those good ol' console days.)

Old World Blues: Stealth Suit MKII

Dead Money: Father Elijah's Robes

Honest Hearts: Joshua Graham's Armor

Lonesome Road: Elite Riot Gear

As for Modded, I'd have to give that one some thought..
I use a handful of armor/clothing mods, but if I had to choose "the" favorite among them;
daejones' Colossus XV BOS Replacer.

I love the color scheme. And enjoy a good number of energy weapons to match with it such as the Rail Cannon from PN, Tactical Laser Rifle, and the Arkarian Weaponry mods, E-88 Plasma Rifle and K-39 Rail Rifle.

Both would be from New Vegas, I'm not a fan of most of the armour in Fallout 3, I've not played any of the older Fallout games and my PC's too much of a pile of junk to run Fallout 4 at consistently good speeds.

Vanilla: NCR Veteran Ranger Armour (Factionless) or Elite Riot Armour. They look sturdy, modern and plausible enough to be carried on a human body, unlike most other kit in game, which wouldn't stand up to a gust of wind, look bang out of the 40's or a grit bin, or look far too heavy to be hauled down a road, much less in a fight.

Modded: Joo's NCR Trooper Uniform (A,B,C) /w S10 Gasmask. I love anything and everything modern military, even if it's lore breaking. ACU Camo, PN Gasmask patch and any sort of modern rifle and it's golden.

My favs are:
1 Scorched sierra Power amor with standard ncr berret and breathing mask FNV
2 both ncr And desert ranger amors (also The advanced And elite riot gear)
3 enclave remnants Power amor

I can't choose between them 'cause I like to use them with different characters and each of them have a unique design and story

Scorched Sierra power armour with 1st Recon Beret for me.