I have plenty of Fallout 3 left to do plus all the DLC, which I'm very much looking forward to, so I'm in no real hurry to get New Vegas at the moment. "Hardcore/Realism" mode sounds awesome though. It would be so sweet if they made that a downloadable feature for Fallout 3. The necessary eating/drinking/sleeping fairly regularly stuff is how I play anyway.
So I've been playing a lot of New Vegas since Election Day (gotta get that we lost feeling out somehow) and over all I'm a little dissapointed with it. Mechanicaly the game is more balanced than 3 was. Weapons are less cut and dry and the modifications are nice, but the world is so much more empty. It seems like the majority of Locations I find are barren, with nothing to do at them. And we've got the loss of the random encounters wich gave you a reaon to walk places instead of fast travel everywhere. It just works out to be a less rewarding game to me. There's plenty of places to explore, but no reason to.
I think after Christmas I'm going to get the Game of the Year 3 so I can play all the DLCs. I only got through Ankorage and The Pitt before my 360 died.