I think that wins the prize for the most hyped remark on HN, ever. Really, the world has not shifted to bitcoin, it won't shift to bitcoin in the near future and possibly never.
Bitcoins are interesting, a very nice implementation of the idea of a digital currency with some thought provoking possible consequences. (See: http://en.wikipedia.org/wiki/Assassination_market), but it isn't a general currency at all, let alone that the world is switching to it.
What you are seeing is that a few companies have caught on to using bitcoin as a way to promote themselves because 'accepting bitcoin' is a way to get free press.
Can you get by for a month just spending bitcoin without any other resources than bitcoins at the beginning of the month, sufficient for a normal months' worth expenses?
When you can go to your local greengrocer and buy an apple with bitcoin I'll cede to you that the world has indeed switched to bitcoin. Until then, it's neat but not quite there yet.
I'll accept payment of US$250 or €250, whichever is the higher value.
The guys at https://www.bitinstant.com/ are in the process of making a debit card backed by bitcoins, so when that's out, you will indeed be able to buy everything you currently buy with a card. However, at that point I still wouldn't agree with the assessment that the world is shifting to bitcoin. For that I'd need to see at least a few billion dollars market-cap, I'd be much more comfortable with a trillion dollar market-cap.