How large is the FNV map compared to Oblivion's map. including more interiors and undergrounds.

I'd say that Oblivions map is twice as large, but with half the content.

Oblivions map is larger it has to be I can't see New Vegas's map being equal in size or larger then Oblivions map.

Oblivion has an epicly large map. The Mohave's no where near as large.
But it's like they just made one square mile's worth of content and copy/pasted it ten thousand times and then lightly sprinkled identical shrines and ruined forts (albeit with different names) across Cyrodil.

I'm discovering FO NV is about interesting stories/quests, not interesting places or a visually interesting map (New Vegas itself being the exception - the casinos are nice enough).

Pretty much what everybody is sayin. Oblivion's map was huge, theres not many games close to the size of oblivions map, but theres not much content within that huge map. where NV is full of content around every corner