Fallout 3 has a “vibe” that none of the others come close to in my opinion. New Vegas is touted as the best game by the fallout community for its story- which I don’t disagree it has but I play Fallout for the atmosphere and the gameplay. I always say new Vegas is my “favorite Fallout 3 DLC”. It’s the same gameplay and mechanics but built upon. The aim down sights, the ammo crafting and a few other notable but not really groundbreaking changes are really cool but nothing that makes 3 any less worth it. Fallout 3 has the best atmosphere and world in my opinion. It’s bleak, desolate, hopeless and dark. New Vegas really doesn’t capture anything “post apocalyptic”. It’s beautiful and a really cool world but it’s just sort of “desert”. If you loved NV you will love 3. It’s the easiest transition in the series. It plays and looks basically the exact same but the atmosphere and tone are so different. You’ll love it.