I'm a massive Fallout fan since I used to play it with my step brother and I even liked Fallout Tactics for a rainy day (Even though it was a totally different style)
What i'm looking forward to is the 'Oblivion' style gameplay with a massive world to explore. Enemies can jump out at any time with no warning. You could help other surviours, follow the storyline missions or simply walk around and loot places for armour and weapons.
There is just something that really excites me about this post nuclear war world. I think its because with games like Fallout and Oblivion, the worlds are so big and you can create the character to be exactly how you would want to be (Hell, I know i'd love to be a slim, toned, brave mutant hunter!) and you can really lose yourself in these worlds...
I'm getting goose bumps just thinking about it