Expanding on the Bombcast from 2-23.
 
Would it be the best thing or worst thing ever to have "Fallout 3" and "New Vegas"  work together?
 
Lets pretend that I could buy "Fallout 3" via XBox games on demand and run "New Vegas" off disc. I would love to have the option to play both pieces of content at once. They said "New Vegas" takes place two years after the prior game. I want to go visit my Tenpenny Tower apartment and loot the now lifeless Lone Wanderer.

You play as a different character so it wouldn't work fiction wise, and I'm pretty sure there is some kind of restriction for booting one game from a different game's disc to prevent game sharing.
 
I didn't like fallout 3 that much at all, I'll probably enjoy New Vegas simply because it'll have bright and flashing lights.

"  I'll probably enjoy New Vegas simply because it'll have bright and flashing lights. "

I don't think that will happen, as obsidian said that they won't take Fallout 3 as cannon with the other games. So no dice. 
 
Unless they said anything after, but i don't think they want Bethesda contributions to "their" franchise.

Washington, DC. -- Las Vegas, Nevada: Different places.

you also can't travel across country. It would be cool if there was a reward for playing through/beating FO3- maybe some armor or a gun or something.

I didn't think it was possible or would happen. I hope for the FO3 save file reward.

" Expanding on the Bombcast from 2-23. Would it be the best thing or worst thing ever to have "Fallout 3" and "New Vegas"  work together? Lets pretend that I could buy "Fallout 3" via XBox games on demand and run "New Vegas" off disc. I would love to have the option to play both pieces of content at once. They said "New Vegas" takes place two years after the prior game. I want to go visit my Tenpenny Tower apartment and loot the now lifeless Lone Wanderer. "

Yeah but it wont happen. :' (