What is your favorite gameplay mechanics of Fallout 3 and Fallout: New Vegas?

My favorite mechanic of Fallout 1/2 was SPECIAL's design, sure it had flaws such as Charisma being pretty much crap for the most part of the game but the other stats could really make or break a character and I liked the brutality of its design. In later Fallout games SPECIAL has become too lenient on the player IMO.

-I like the Companion wheel a lot. I hope to see it again

-I like the traits in FONV.

-I like the idea of iron sights but it was poorly implemented. There really is no reason to actually use iron sights other than it looks cool. There should be actual reasons like better accuracy.

-I liked Gambling. I want it back please

-The third person view is nice, but I wish it received a few upgrades.

-I loved the radio addition. More should come from this, suggestion is to remove the radio buttons and make it so you need to tune in to get to a station. Would be awesome if you had to write down the radio stations you need to tune too.

-I like the Fallout 1/2 dialogue system more (well the dialogues that would end gameplay and it would have a close up on their face).

Good thing you didn't ask about least favorite

I liked healing over time and ammo weight in harcore mode, radio, traits and perks, speech checks in NV.

Btw, I've heard, that ironsights and companion wheel are in fact Bethesda design. On the other hand, source of this information is a really devoted fan, so I don't really know. Either way, I don't care about both things.

I liked damage threshold and the changes to weight, healing and companions in New Vegas' HC mode, as well as the general ideas behind skillbased dialogue options, crafting and cooking. But I still wish they had (and will in the future) designed these mechanics - all the skill and stat effects - as more defining the character; much greater gameplay impact across the board. Aside from dialog (in NV) they leave a cold and carefree feeling, when it really should be the other way around.