IGN has rounded up a list of reasons why they think Fallout: New Vegas should be invoking a lot of excitement in the gaming world. I have to admit, hardcore mode sounds like it'll make for an entertaining (and realistic) second play-through:
There's a funny argument against Fallout 3 that goes something like this: Once you reach the level cap the game is too easy. Or, as I like to put it, once you have created a badass character he's too much of a badass. Well, for all of you people that were simply too good at Fallout 3, meet Hardcore Mode.
This new level of difficulty being added for Fallout: New Vegas is for anybody that loves a challenge. It may as well be called Realism Mode. Everything has weight, even ammunition. You'll have to eat food and drink water regularly to stay alive. Stimpacks won't heal instantly, so you won't be able to spam them in the midst of a fight. And if you break a bone, you'll need a doctor and some bed rest to heal it.
Sounds rather punishing to me, but I'm sure there will be some folks out there that will accept the challenge.