My main mods for New Vegas:
Active Wasteland - makes it possible to interact with some object like lamps, hydrants, coffee machines etc...
Burning Campfire - when you activate a campfire, it'll burn for a while
Delay DLC - stops annoying messages "This DLC has been loaded. Level cap increased", instead it prevents them from loading unless you get to close to its starting location or your level is high enough
Sheriff Meyers - a simple mod which gives Meyers a true sheriff outfit instead of letting him wear his Powder Ganger armor when he becomes a sheriff
NPCs travel - adds a bunch of respawning travelers, making FNV a less desolate place. At first I liked that Mojave is more or less deserted but with time I was longing to see some life in the desert
Frequency of assassination attempts - a mod that lets you choose how long you want intervals to be between Legion/NCR hit squads. I have mine set to 21 days, default is 3
Grimy Pre-War Businesswear fix - in the vanilla game a wrong texture is used so all businesswears have the same texture, this mod fixes it and uses the appropriate texture
Hall of Face - HiRes faces, eyes,...
Headgear Revamp - makes it possible to wear certain headgear together
Karma Killing Fix - you no longer get rewarded with good karma for killing Fiends
Leather backpack - adds a leather backpack to the game, obviously, one also involves a mattress, so you can sleep anywhere
Merchants repair any armor - even those without any DT
More seatable couches - you can't interact quite a few of them in the base game
Mojave Radio and
FNV Radio extenders
Nights are Darker - ...
Nipton Revisited - clears burning fire and removes crucified victims after some time passes
No Empty Message - removes the annoying empty message from containers
Extra Actions - allows you to open safes with explosives, force lock with melee weapons etc...Find links for other mods in the Description section
PipBoys to the people - adds PipBoys to some people that should have them in first place
Primm Reputation Restored - for some reason Primm Rep was cut from the final release
Radial Blur Remover - removes annoying blur when hit or in VATS
Real Smokes - adds smokeable cigarettes
ReElijahfied - makes Elijah looks like he looks on the hologram
SCC - allows you to recruit any NPC. Must be used in conjuction with SCC Heal Fix because the original version doesn't allow you to heal followers
Screen Blood - Optional Plugins - removes blood from screen when hit. The newest version is complicated and comes with too many features of if someone's interested in merely removing blood, you have to use an older version of the mod
Shorter Chem Wear Off effects - does what it says
Sheriff Duster - increases its DT
Sit Anywhere - press X and sit down anywhere
Solar's Bottled Water - allows you to bottle water
Mods from
Someguy2000 - New Vegas Bounties I & II,
The Inheritance? (the best quest mods for FNV IMO)
Stronger Merchants - they no longer get killed that easily
The Strip Credit Check - increase it to 5000 or 10000
Throw and Retrieve - allows you to retrieve thrown items if the target was hit. Works well with Throwing Knives replenishment which adds TKs to merchants and raiders
Ultimate Invisible Wall Remover - removes some invisible barriers
That's most of them. I use some body replacers, Breeze for males and Dimonized Type 3 for women and corresponding armor sets, I also use unofficial patches which I didn't list above.
I'm still looking for a mod that'd allow you to sleep anywhere without requiring a mattress or a perk from Lonesome Road DLC. Something like blankets from Fallout 3. Hopefully someone will port this mod one day.