my favorite part of fallout 3 was exploring the metro and underground tunnels, bunkers and the larger buildings like the schools etc, for me these were the places with the most atmosphere and kept me coming back again and again, to be honest exploring the exterior of fallout 3 due to its size and the lack of a vehicle was less interesting, will new vegas feature as many interior places to explore? i have heard there will be no metro, to my mind a mistake!
There is something similar to the metro but it's completely optional.
Edit: Woot! this my 100th post today. :celebration: