If you're referring to the Mayan "prediction"...
First, you must consider a few things:
1. Modern man isn't really able to fully understand what the Mayans might have meant.
2. Much of the Mayan works that could shed light on the subject were destroyed.
3. From what we know, the Mayans held a lot of stock in cycles. The long count calendar (and all their shorter ones) were circular. Meaning, more than likely, the long calendar will start back at day 1 (or the Mayan equivilant).
I personally, am going to live my life as though life will continue. I'd rather be prepared to continue paying my bills, saving for retirement and continuing education for my children, and collecting a lot of astronomy stuff.
Will we all die? Probably not, in my opinion.
Will something happen to change life as we know it? Quite possibly. Hopefully, it'll be change for the good, but even if it's not, I am pretty sure man kind, and life on Earth, will continue.