I take it with a grain of salt. I used to know a lot more about it than I did now, but it's best to know more about it than just simply coming out and stating any answer, yes or no. The movie prolly didn't help, either.
There are heaps and heaps of things that can happen...the main being the poles shifting which is gonna cause everything else from natural disasters to a shift in living consciousness. It's not all just your natural disasters and solar flares, but as well as scavengers and looters after the SHTF(**** hits the fan) who want your resources, global flooding(I wish I could find the map of it displaying what it could possibly look like after the poles melt), radiation from nuclear fallout, as well as a NWO that could re-emerge and create a totally new problem...I could go on more about this.
If you are more concerned on it's validity, I suggest reading some authors like Robert Bast, or if you don't care for books, look straight up on the internet...the Mayans, for instance. There is a wealth of knowledge on them, not just on their calendars. Then there's a wealth of knowledge on 2012 and NWO in general, and then some.
I still feel inclined to have preparations...having an underground bunker is great, as well as knowing how long you can last with your supplies in storage. Don't hunker down in a cave with your supplies because flares and radiation can always find it's way in. If the above were to happen, no animals will probably be alive where you are so hunting is mostly out of the question.
I prefer planning all these things, but not completely for when the SHTF. Bunkers and survival knowledge helps with anything else that could happen besides it, and can provide a safe way in case of natural disasters(for flooding...not so much).
I do not fear it and it does not control what I plan for myself in the far future. As far as I'm concerned, it's not gonna happen, but I'm not gonna completely ignore it, either.