Thought I would revive this thread with some discussion on some newer mods released for New Vegas (released in 2015 - the last few weeks) I have found to be fantastic.
Behaviours (
http://www.nexusmods.com/newvegas/mods/61925/) - Mod author Fallout2AM who is best known for heaps of animation mods released this mid-year and it's so awesome. Basically adds idle animations for your character, while they are walking or standing still. Fully customisable in MCM and you can choose which idles play (swatting, hands on hips, smoking, crying, staring off into the distance, sitting, etc). There's also an experimental head-tracker included (your character will stare at nearby NPCs). Severely under-downloaded.
Iguazu Shopping Center - A Mall in The Strip (
http://www.nexusmods.com/newvegas/mods/62317/) - Mod author Jokerine has a ton of similar mods adding life to the Mojave with new businesses, and this is his latest. Adds a really cool shopping centre to the North Strip, tons of detail, new NPCs, textures, voice-acting and all-around effort put in.
Lively Gourmand And Street Vendor Stall (
http://www.nexusmods.com/newvegas/mods/62336/?) - Mod author BlooperReel added a cool street vendor stall in the main part of the Strip, and made the Gourmand within the Ultra-Luxe Casino more lively and feel more like a restaurant.
Mojave Outpost Redesigned (
http://www.nexusmods.com/newvegas/mods/59623) - Another mod by BlooperReel, I only found this recently and it's severely under-downloaded. He spruced up the Mojave Outpost with tons of new NPCs, decorations, merchants, bugfixes and gave all of the inhabitants custom animations so it feels more alive. There's now assistants for the NCR stationed there on the type writers, merchants outside eating or walking around, some new NPCs with voice-acting, and so on.
Real Recoil (
http://www.nexusmods.com/newvegas/mods/62153) - Adds a proper recoi system to New Vegas, and mod author Deus Gladiorum has gone the extra mile with consistent compatibility updates.
Saints and Sinners - Karma Consequences (
http://www.nexusmods.com/newvegas/mods/62186/) - Mod author PushTheWinButton made a mod which awards karma perks for neutral, good, evil, very good and very evil. You get benefits, but also hit squads come after you depending on your karma, similar to Fallout 3.
Simple Reputation and Disguises (
http://www.nexusmods.com/newvegas/mods/62183) - Makes much needed tweaks to the faction disguise system, and can be safely disabled or enabled mid-game without any issues if you don't like it. Another really well implemented mod from author PushTheWinButton.
The New Vegas Reborn Project (
http://www.nexusmods.com/newvegas/mods/59631/) - A rebalancing mod which has since been replaced with another mod, JSawyer Ultimate, made by the same mod author, PushTheWinButton. I recommend it for one of its modules, "Mojave Encounters", which adds dynamic random encounters into the game.
Less Lame Tops Pool (
http://www.loverslab.com/files/file/616-kendo-2‘s-less-lame-tops-pool/) - Might be a bit more risque for some people's tastes, but I think it adds some life to the courtyard within the Tops Casino. And it actually isn't as pervy as the download page makes it seem.