1. Arwen's Tweaks
Because I like struggling to survive instead of mowing down armies of raiders and becoming super-rich immediately. Without it the game's just too arcadey, easy and boring. Naturally it took me a fair bit of tweaking to get it to work with TTW and I've barely started on distributing the MedTec items, but I simply wouldn't play without Arwen's hardcore mode.
2. Any simple 3x damage upper
Because I hate the RPG-trope style combat where you stand there trading headshots until one of you runs out of HP. I like my combat to be fast and deadly, and my non-combat travelling and exploration to be tense and wraught with terror. If I can shrug off a surprise .308 to the head, I might as well just sprint around the place with my eyes closed and my thumb up my butt.
3. Project Nevada
Because I've just gotten too used to the gameplay features it brings. Grenade hotkeys, visor overlays, sprint key... they seem like a mandatory part of the game to me now, and I'd miss them terribly.
5. Graphical mods ; DarnUI, weather replacers, body replacers, texture replacements, etc.
Because, pretty.
6. FNNCQ Slavery Overhaul
Because I've never played a non-evil PC and I probably never will.
7. Assorted weapons tweaks ; 00 Commando, Weapons Mod Menu, Manual Reload, Selective Fire
For better, more immersive and less cheaty combat.